Your troubleshooting list is excellent and exactly what QA needs to locate and evaluate potential bugs. If this is a bug, then it will get fixed when it is fixed for all accounts in a patch. The way to report bugs is to post this (or move your thread) to the Console Bug Report forum.
This thread seems like some others also have similar issues.
Blizzard does not provide individual account assistance for Diablo games (or any others besides WoW) for in-game issues. They only provide that for very limited issues in WoW.
Tech Support, is for getting the game running on your platform, and resolving crashing issue. They don’t handle Bug Reports.
To move your thread to Bug Reports, select the edit button on your post (pencil icon). Then use the drop down list to change the forum selection from Tech Support to Bug Report.
QA does not usually reply, but that is how to report something you think is bugged.