serve_site() fails to render when using any function from keras package in Rmd

(Since I didn't get a reply to my Github issue https://github.com/rstudio/blogdown/issues/473 I'm trying again here.)

As soon as I include any code from the keras package in my Rmd, I get the following error when trying to serve my blogdown site with blogdown::serve_site():

Rendering content/post/keras.Rmd
Error in render_page(f) : 
  Failed to render 'content/post/keras.Rmd'

This is an example but it happens with any keras function, like image_data_generator() (running it in my R console or from the Rmd codechunk works as expected:

library(keras)
is_keras_available()

Here is a link to my Github repo and the Rmd file in question

> xfun::session_info('blogdown')
R version 4.0.2 (2020-06-22)
Platform: x86_64-apple-darwin17.0 (64-bit)
Running under: macOS Catalina 10.15.6, RStudio 1.3.1073

Locale: en_US.UTF-8 / en_US.UTF-8 / en_US.UTF-8 / C / en_US.UTF-8 / en_US.UTF-8

Package version:
  base64enc_0.1.3 BH_1.72.0.3     blogdown_0.20.1 bookdown_0.20   digest_0.6.25   evaluate_0.14   glue_1.4.2      graphics_4.0.2  grDevices_4.0.2
  highr_0.8       htmltools_0.5.0 httpuv_1.5.4    jsonlite_1.7.1  knitr_1.29      later_1.1.0.1   magrittr_1.5    markdown_1.1    methods_4.0.2  
  mime_0.9        promises_1.1.1  R6_2.4.1        Rcpp_1.0.5      rlang_0.4.7     rmarkdown_2.3   servr_0.18.1    stats_4.0.2     stringi_1.5.3  
  stringr_1.4.0   tinytex_0.25    tools_4.0.2     utils_4.0.2     xfun_0.17       yaml_2.2.1     
> devtools::session_info()
─ Session info ───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────
 setting  value                       
 version  R version 4.0.2 (2020-06-22)
 os       macOS Catalina 10.15.6      
 system   x86_64, darwin17.0          
 ui       RStudio                     
 language (EN)                        
 collate  en_US.UTF-8                 
 ctype    en_US.UTF-8                 
 tz       Europe/Berlin               
 date     2020-09-09 
─ Packages ───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────
 package     * version date       lib source                           
 assertthat    0.2.1   2019-03-21 [1] CRAN (R 4.0.0)                   
 backports     1.1.9   2020-08-24 [1] CRAN (R 4.0.2)                   
 base64enc     0.1-3   2015-07-28 [1] CRAN (R 4.0.0)                   
 blob          1.2.1   2020-01-20 [1] CRAN (R 4.0.2)                   
 blogdown      0.20.1  2020-09-09 [1] Github (rstudio/blogdown@d96fe78)
 bookdown      0.20    2020-06-23 [1] CRAN (R 4.0.2)                   
 callr         3.4.4   2020-09-07 [1] CRAN (R 4.0.2)                   
 cli           2.0.2   2020-02-28 [1] CRAN (R 4.0.0)                   
 crayon        1.3.4   2017-09-16 [1] CRAN (R 4.0.0)                   
 curl          4.3     2019-12-02 [1] CRAN (R 4.0.0)                   
 DBI           1.1.0   2019-12-15 [1] CRAN (R 4.0.0)                   
 dbplyr        1.4.4   2020-05-27 [1] CRAN (R 4.0.2)                   
 desc          1.2.0   2018-05-01 [1] CRAN (R 4.0.0)                   
 devtools      2.3.1   2020-07-21 [1] CRAN (R 4.0.2)                   
 digest        0.6.25  2020-02-23 [1] CRAN (R 4.0.0)                   
 dplyr         1.0.2   2020-08-18 [1] CRAN (R 4.0.2)                   
 ellipsis      0.3.1   2020-05-15 [1] CRAN (R 4.0.0)                   
 evaluate      0.14    2019-05-28 [1] CRAN (R 4.0.1)                   
 fansi         0.4.1   2020-01-08 [1] CRAN (R 4.0.0)                   
 fs            1.5.0   2020-07-31 [1] CRAN (R 4.0.2)                   
 generics      0.0.2   2018-11-29 [1] CRAN (R 4.0.0)                   
 glue          1.4.2   2020-08-27 [1] CRAN (R 4.0.2)                   
 htmltools     0.5.0   2020-06-16 [1] CRAN (R 4.0.2)                   
 jsonlite      1.7.1   2020-09-07 [1] CRAN (R 4.0.2)                   
 keras       * 2.3.0.0 2020-05-19 [1] CRAN (R 4.0.2)                   
 knitr         1.29    2020-06-23 [1] CRAN (R 4.0.2)                   
 lattice       0.20-41 2020-04-02 [1] CRAN (R 4.0.2)                   
 lifecycle     0.2.0   2020-03-06 [1] CRAN (R 4.0.0)                   
 magrittr      1.5     2014-11-22 [1] CRAN (R 4.0.0)                   
 Matrix        1.2-18  2019-11-27 [1] CRAN (R 4.0.2)                   
 memoise       1.1.0   2017-04-21 [1] CRAN (R 4.0.0)                   
 pillar        1.4.6   2020-07-10 [1] CRAN (R 4.0.2)                   
 pkgbuild      1.1.0   2020-07-13 [1] CRAN (R 4.0.2)                   
 pkgconfig     2.0.3   2019-09-22 [1] CRAN (R 4.0.0)                   
 pkgload       1.1.0   2020-05-29 [1] CRAN (R 4.0.2)                   
 prettyunits   1.1.1   2020-01-24 [1] CRAN (R 4.0.0)                   
 processx      3.4.4   2020-09-03 [1] CRAN (R 4.0.2)                   
 ps            1.3.4   2020-08-11 [1] CRAN (R 4.0.2)                   
 purrr         0.3.4   2020-04-17 [1] CRAN (R 4.0.0)   
R6            2.4.1   2019-11-12 [1] CRAN (R 4.0.0)                   
 Rcpp          1.0.5   2020-07-06 [1] CRAN (R 4.0.2)                   
 remotes       2.2.0   2020-07-21 [1] CRAN (R 4.0.2)                   
 reticulate    1.16    2020-05-27 [1] CRAN (R 4.0.2)                   
 rlang         0.4.7   2020-07-09 [1] CRAN (R 4.0.2)                   
 rmarkdown     2.3     2020-06-18 [1] CRAN (R 4.0.2)                   
 rprojroot     1.3-2   2018-01-03 [1] CRAN (R 4.0.0)                   
 rstudioapi    0.11    2020-02-07 [1] CRAN (R 4.0.0)                   
 sessioninfo   1.1.1   2018-11-05 [1] CRAN (R 4.0.0)                   
 tensorflow    2.2.0   2020-05-11 [1] CRAN (R 4.0.0)                   
 testthat      2.3.2   2020-03-02 [1] CRAN (R 4.0.0)                   
 tfruns        1.4     2018-08-25 [1] CRAN (R 4.0.0)                   
 tibble        3.0.3   2020-07-10 [1] CRAN (R 4.0.2)                   
 tidyselect    1.1.0   2020-05-11 [1] CRAN (R 4.0.0)                   
 usethis       1.6.1   2020-04-29 [1] CRAN (R 4.0.0)                   
 vctrs         0.3.4   2020-08-29 [1] CRAN (R 4.0.2)                   
 whisker       0.4     2019-08-28 [1] CRAN (R 4.0.0)                   
 withr         2.2.0   2020-04-20 [1] CRAN (R 4.0.0)                   
 xfun          0.17    2020-09-09 [1] CRAN (R 4.0.2)                   
 yaml          2.2.1   2020-02-01 [1] CRAN (R 4.0.0)                   
 zeallot       0.1.0   2018-01-28 [1] CRAN (R 4.0.0)                   

[1] /Library/Frameworks/R.framework/Versions/4.0/Resources/library
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