Previewing a tibble in an R Notebook

I would like to print a tibble in a preview of an R Notebook, but not in the paged format. It ends up with a lot of extra [3m[38;5;246m<dbl>[39m[23m junk.

---
output:
    html_notebook: default
    html_document:
      df_print: paged
    pdf_document: default
---

```{r, paged.print=FALSE}
tbl_cars <- as_tibble(mtcars)
tbl_cars
```

Inline Chunk output is correct:

A tibble: 32 x 11
       mpg   cyl  disp    hp  drat    wt  qsec    vs    am  gear  carb
     <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl>
 1  21       6  160    110  3.9   2.62  16.5     0     1     4     4
 2  21       6  160    110  3.9   2.88  17.0     0     1     4     4
 3  22.8     4  108     93  3.85  2.32  18.6     1     1     4     1
 4  21.4     6  258    110  3.08  3.22  19.4     1     0     3     1
 5  18.7     8  360    175  3.15  3.44  17.0     0     0     3     2
 6  18.1     6  225    105  2.76  3.46  20.2     1     0     3     1
 7  14.3     8  360    245  3.21  3.57  15.8     0     0     3     4
 8  24.4     4  147.    62  3.69  3.19  20       1     0     4     2
 9  22.8     4  141.    95  3.92  3.15  22.9     1     0     4     2
10  19.2     6  168.   123  3.92  3.44  18.3     1     0     4     4
… with 22 more rows

Preview output:

[38;5;246m# A tibble: 32 x 11[39m
     mpg   cyl  disp    hp  drat    wt  qsec    vs    am  gear  carb
   [3m[38;5;246m<dbl>[39m[23m [3m[38;5;246m<dbl>[39m[23m [3m[38;5;246m<dbl>[39m[23m [3m[38;5;246m<dbl>[39m[23m [3m[38;5;246m<dbl>[39m[23m [3m[38;5;246m<dbl>[39m[23m [3m[38;5;246m<dbl>[39m[23m [3m[38;5;246m<dbl>[39m[23m [3m[38;5;246m<dbl>[39m[23m [3m[38;5;246m<dbl>[39m[23m [3m[38;5;246m<dbl>[39m[23m
[38;5;250m 1[39m  21       6  160    110  3.9   2.62  16.5     0     1     4     4
[38;5;250m 2[39m  21       6  160    110  3.9   2.88  17.0     0     1     4     4
[38;5;250m 3[39m  22.8     4  108     93  3.85  2.32  18.6     1     1     4     1
[38;5;250m 4[39m  21.4     6  258    110  3.08  3.22  19.4     1     0     3     1
[38;5;250m 5[39m  18.7     8  360    175  3.15  3.44  17.0     0     0     3     2
[38;5;250m 6[39m  18.1     6  225    105  2.76  3.46  20.2     1     0     3     1
[38;5;250m 7[39m  14.3     8  360    245  3.21  3.57  15.8     0     0     3     4
[38;5;250m 8[39m  24.4     4  147.    62  3.69  3.19  20       1     0     4     2
[38;5;250m 9[39m  22.8     4  141.    95  3.92  3.15  22.9     1     0     4     2
[38;5;250m10[39m  19.2     6  168.   123  3.92  3.44  18.3     1     0     4     4
[38;5;246m# … with 22 more rows[39m

Knit to HTML and Knit to PDF output are correct

MacOS 10.13.6 and 10.14.6
RStudio 1.2.1335 and 1.2.1565
R 3.6.1