I had just updated R and RStudio to the latest versions a week or so before these issues and didn't see the problems until 6 days ago. I've since updated all the R libraries used and the issue remains, plus now there's a new issue where all the figures generated in the rmarkdown code have the axis scales and titles cut off and just the plot portion of the figure filling the page margins. Something is seriously wrong with my set up. I went to the
C:\myDesktop\Data Analysis Book_bookdown_files_main_files\figure-latex
folder where the generated figures' .png files are stored and the .png files also have the axis scales and titles missing, so that seems like an Rmarkdown/png generation issue. This is getting to be like the Cat in the Hat where everything I do seems to make it worse. I'll try reinstalling R and RStudio and try again.