Without focus highlighting on many links, it is hard to tell, but it looks like tabbing is currently not respecting tabIndexes (tabIndices?)
Going from a title to a post box or from the post box to the "Post Reply" button is not working. This has started very recently, as I use <tab><space> to post and I haven't noticed it until this evening.
Windows 10 x64
Version 62.0.3202.94 (Official Build) (64-bit)
No Forum Stylesheet
I do use uBlock, but the issue presents itself with uBlock disabled as well
Apple is a terrible company.