I've seen this problem pop up on several occasions. Usually it's pretty minor and doesn't impact a large number of addons. But this time it's happened on a fairly large basis.
I'm sorry sylvanaar, I'm going to pick on you to a certain extent but you're by far not the only author doing this. You're just the most recent person to have caused a major problem with it.
AceGUI-3.0-SharedMediaWidgets had some work on it. At some point in the process of this work the library had a Lua error in it. This entirely broke the library. In this particular case the breakage causes the dropdowns to obviously break and to also cause massive frame rate losses until someone reloads the UI. The most recent release version of Prat-3.0 unfortunately has been shipping with this broken version of the library for 2 weeks now.
The library has long since been fixed. Prat has an alpha version with the new version of the library but the release version is still shipping with this broken library.
So how did we get here? We got here because Prat's .pkgmeta looks like so:
The important difference is the addition of tag: latest.
This means that you will at least only get the most recent tag (possibly beta but at least something that a human being thought was worth tagging). Not just whatever the most recent alpha version of the library is.
Now I'm sure some people are going to come back and say "Some libraries aren't getting tagged." Which brings me to my plea to everyone.
1) Library authors, please either tag or clearly specify in your documentation that you will not be tagging. Realize if you're not tagging that you're likely to have a mess with your library anytime a major addon update includes an alpha version where you broke something.
2) AddOn authors. Use tag:latest unless you have a very good reason (e.g. library is never tagged, you depend upon the alpha version for some reason).
We have these features on wowace to make our lives easier. Let's use them.