Oddities with "pool:*" searches

I tried doing a search with a wildcard pool name (specifically, "pool:touhou*)", to try and match Series touhou pools) and noticed odd behavior. The results I get with a * are far fewer than I would expect to get.

For example, "user:qazmlpok pool:*" gives me exactly two images, however I've uploaded a decent number of images in various pools. "user:qazmlpok pool:any" seems to work correctly and seems to give all of the expected results. I have no idea what makes the two images in "pool:*" special, either.

I would expect those two searches to be equivalent, but they aren't. I can't simply use "pool:any" for what I have in mind, as I need to be able to refine the wildcard on the pool name.

Is this a known issue, or possibly an intended feature?

The wildcard does not actually work as you'd intuitively expect - it limits the number of tags checked to your tag query limit (presumably for performance reasons). This applies to both the pool: wildcard and regular tag wildcards.

For example, if you do a post search for s*, you would expect that any post with any tag beginning with the letter S be returned. In reality, it just picks the biggest tags starting with S and searches for posts with any of those tags. If you're a basic member it will only pick the 2 largest tags. If you're gold it picks the 6 largest. If you're platinum+ it picks the 12 largest. Since there are a total of 24109 tags beginning with S, even 12 isn't even close to being all of them.

In the case of user:qazmlpok pool:* it picks the 6 largest pools on the site (these 6) and then filters those posts down by which you have uploaded.

tl;dr You need to make your wildcard searches more specific. Very broad wildcard searches will not work right.

Ah, that'd certainly explain things. That's problematic though, as what I was trying to do requires the wildcard to match a large number of pools. pool:any works but is too generic, and there sadly doesn't appear to be a pool:series. Drat.