Any macro, no matter how simple (including an empty macro) that I put on my main bar, shows a flickering hotkey label.

There's no flicker on secondary bars, or on un-macro'd abilities.

Dannez's fork has this commit, which purported to fix the flickering, but I can't easily tell if this made it into the now-published release.
Dannez83@e82018f

@durandal42 It wasn't put in the release. You need to comment out the "if" statement starting at line 257 and ending 274 in src\engine\mega-macro-action-bar-engine.lua. Be careful not to comment out the function "end" on line 275

amended file if you just want to replace it
mega-macro-action-bar-engine.zip

this fix works for me. thx Dannez83