I reported this issue a year and a half ago, and bumped it multiple times with months between each and never get an acknowledgement or response.
Some of the people responding here aren't fully understanding what the issue is though. It's not about how easy/hard it is to keep Timurid vassals loyal, it's about Transoxiana being able to receive independence support from Uzbek during the first month (Nov. 1444) despite being loyal (<50% liberty desire) because it's attitude starts out disloyal and won't change until the month tick to December. Attitude trumps liberty desire, so a vassal with 0% liberty desire yet a hostile attitude can receive independence support, and alternatively a 100% liberty desire vassal with a loyal attitude can't.
Altering vassal attitudes so that they change immediately when liberty desire goes above or below 50% seems to be difficult to do/resource-intensive, but there's a very obvious solution here I previously suggested. Just change Transoxiana's starting vassal attitude to "loyal" yet with the same >50% starting liberty desire. This way, a skilled player can avoid the independence support provided they get the liberty desire below 50% before December 1st, but the AI may still struggle with instability if it fails to do this.
This is not WAD unless a supposedly "loyal" vassal (<50% LD) is supposed to be allowed to receive independence support because a month tick hasn't occured to update its vassal attitude.
And yes, as mentioned above by
@TheMeInTeam , even when you get Transoxiana's LD below 50%, Uzbek's support won't go away unless you dec on them.