User Sjögurka from Twisting Nether (EU) sent in this message with a fix; hopefully it helps some people:
“Today I got a whisper from a friend of mine that said there are errors in CT_BottomBar. I investigated and it seems that Blizzard managed to introduce some bugs/changes to the slider XML object in 5.4 which broke the CT code. I have applied a fix to CT_Library library (and incremented version number of the file from 5.0002 to 5.0003) to accommodate for this change. The file is in the link below.”
Here’s a link to the updated CT_BottomBar as well. The .toc is likely still outdated so you will probably have to enable outdated add-ons.
Hope that helps a few people!