Apple ID picture changes unexpectedly

I've had this happen a few times, and have seen quite a few posts on this board and others with the same noting the same phenomenon: My Apple ID picture changes without any action on my part. I have a little sketch I use for me. I didn't do anything and yesterday I went to log on to my computer and it was a rose. Today it was blank. This isn't the worst problem to have, but malfunctions, especially regarding my Apple ID do raise concerns of stability if not security.

A common thread of people with the problem is being part of a iCloud family. However we do not share any devices or accounts.