Of course you could also take a slightly wider view and say that a list of global blocks on Wikimedia wikis provides a list of valid proxies to vandalize non-Wikimedia wikis. I'm not sure this is a reasonable concern.

This is not a concern with the type of proxy we're blocking and the way we're blocking it -- that's the best I can say publicly. And more broadly speaking, publicised lists of proxy exit IPs are likely to be substantially more useful to defenders than to attackers anyway.

It's intermittent for me, but I can reproduce.

One of my primary communication concerns is the way that layered blocks are currently handled. We want to be able to block individual exits with highly informative block messages. We can do that (and are doing that), the issue is that if they are on an underlying range that is already blocked for one reason or another, (enwiki) users see the following, which is a transclusion of https://en.wikipedia.org/wiki/MediaWiki:Blockedtext-composite.

@Srdjan and I did some testing (see https://bs.wikipedia.org/wiki/Posebno:Doprinos/Blablubbs) -- I can move pages fine both with and without the autoreview flag, so assigned user groups don't seem to be the cause.

@ppelberg I've given it a couple days to see that it's working reliably, and indeed it is. I think this can be closed -- thanks for the fix :).

Well, sorry for the spam but it's broken again. I'll just report back once it's been working consistently for a couple days.

Update 2: Has since dropped in and out a couple times, but has been functioning consistently today -- I assume the fix was pushed and is working. @ppelberg Thanks for fixing this so quickly, I think the issue can be closed.

Update: Now started working again.

Will do @ppelberg; thanks for the quick response!

Indeed, that was the edit -- I had enabled enterprisey's reply-link for a while and just uncommented the line so I could just wait and see when it would start working again. Some time after uncommenting, it actually worked for a bit -- see e.g. the tags here https://en.wikipedia.org/w/index.php?title=User_talk:Blablubbs&diff=prev&oldid=1002953117. I'll keep you up to date in case it unbreaks again.

The patch appears to have fixed the issue for a short while, but it looks like it broke again - at least for me.