iCloud Messages size inflating from seemingly nothing

[ThatSomeone]

For the past few weeks my iCloud storage has been completely eaten up by "messages". It's increased by ~100mb every few days for a short while now with absolutely nothing that could possibly attribute to it. In fact, I've deleted about 40+ attachments since it started, and I've also deleted any new ones to stop this mysterious growth. But it just keeps growing, and now I've ran out of space! According to my iPhone, "top conversations" should use ~700mb(it's only 36mb on my iPad and Mac shows nothing?). Yet, messages in iCloud currently sit at over 1.9GB and counting. And I've also gone into the "Deleted messages" pane and confirmed deletion.

Does anyone have any idea on what's going on here? Is this happening to anyone else?

 

[ThatSomeone]

I called AppleCare today who really didn't seem to want to help solve this issue. First rep just scoffed when I tried to explain it and the senior advisor tried convincing me that it was my fault that my current old conversations had doubled in size in only a few weeks despite my efforts to do nothing but remove as much as I can... Really don't know how to proceed here apart from upgrading the storage.