User blog comment:DaNASCAT/Technical Update: April 6, 2016/@comment-1251315-20160406203451/@comment-11733175-20160407152312

If you want a comparison, runescape: has SMW now. I've been asking around and we've seen no issues, so it may be a bit more complicated than simply having SMW installed.

Edit: I had a quick play with the sample pages you linked to. It's reminiscent of when DPL does something extraordinarily heavy on the servers. I'd suggest there's something subtle that's changed at a very low and seemingly unrelated level.

I had a browse through some recent commits and the only thing that leapt out at me was a very minor change in the ParserCache and some alterations to error logging. I doubt it's either of these.