While testing the package with R-devel on Linux via GitHub Actions, the error occurs while trying to create/update documentation via devtools::document():
Error in nchar(xs) :
number of characters is not computable in "bytes" encoding, element 1
The error message is not informative and does not indicate which lines of code create the issue. How should I start debugging and fixing this?
On R-oldrelease and R-release this error is not present. On my Windows machine, R CDM check is successful. Summary of the issue in the image below, link to report is here

If you have any ideas, please, share.