Strange tag changes

Noticed this on post #1480147 and post #1480127 after the downtime, but according to tag histories these posts got radically changed.

Knowing the users "involved", I'll guess this is just some bug in the system and not done with malicious intent.

*edit*
Other posts:
post #1480101

*edit edit*

solo is showing 1 post for post #1480042
*edit again*
So I looked at the tags for post #1480042, and there was a double (triple?) space. I removed it, saved, and the tags came back as normal. Very strange.

Strange that 3/4 of these bugged changes were made by the same user.

Kikimaru said:

solo is showing 1 post for post #1480042

That wasn't actually the solo tag, it was "solo" + an invisible character at the end. The other tags on that particular post all had other strange characters as well. I fixed that post.

Technical details:

I switched to a new version of the memcache client library Danbooru uses. This new version uses a different protocol and there was a window of about 30 seconds where I forgot to flush the cache. There's an incompatibility between the two versions which I believe this is the source of the strange characters. They should not be appearing in any new post updates.

What I'm doing:

I'm going through and stripping these strange characters where I can find them. If you can point out problematic posts I'll try and fix them.