They forked an old version of Forge just to put this fix in.
So yes, I am sure.
The issue isn't "Fake Air," the issue is invisible tile entities. You don't see this with a lot of mods because they don't have multiple tile entities with GUIs on the same block ID. The mods that do get screwed royally by the current vanilla behavior.
It has nothing to do with block movement, as normal blocks will overwrite the air and kill the entity without issue. Tile Entities placed on top of Tile Entities don't do that properly. Or rather they do, but the client doesn't get to hear about it. Hence, the issue.
EDIT: Part of it is that people for the most part don't get the debugging process. That's not a slight, just that the average player doesn't think like a programmer. The fluid sync bug has also existed for 5 months, but it wasn't until about a week ago that the real cause was figured out - alphabetizing of mod names is different on Linux/Windows, leading to different load orders, and mucking everything up. And yet, for 5 months, people accepted it as "weird."