For the first bug, this happens because of a legacy feature still hanging around where meta files are ignored in Version Control (which for some reason also includes this in editor). To solve this, go to Project Settings > Version Control > Mode from "Hidden Meta Files" to "Visible Meta Files", the issue should disappear.
For the second bug, there is a limit to how big an entity can be, because there is a limit on how big a chunk can be. In this case the AudioBuffer itself is not so much the problem, as adding that buffer makes the entire entity too big to fit in a chunk. I would advise splitting this entity in two, perhaps with links between them if necessary.