OK, apparently a update to improve search perforrmace was recently installed, which is mostly working really well, except for this issue. It's being worked on right now.
Interestingly, I had noticed that moderation stuff was working much better, not killing the rest of the forum when I ban people (loads of spammers this morning!), so apart from this one issue, it looks like a good upgrade.
Principal Software Engineer at Raspberry Pi (Trading) Ltd.
Contrary to popular belief, humorous signatures are allowed. Here's an example...
"My grief counseller just died, luckily, he was so good, I didn't care."