Windows 10 Pro / Intel(R) Xeon(R) CPU / 2.53GHz / 16.0GB RAM / 64bit
these are what's happening. It suddenly happened like that two days ago.
I even re-packed into new items, reset skeleton&animation, reinstalled the viewer, reset cache/clearing cache, and rebooting, nothing was able to solve the problems in those links.
Strange thing is, only several my avatar attachments are broken like that. Other objects and users' attachments are rendering properly.