I'm putting together a one-shot that I'm supposed to be running on wednesday in which the party will be fighting a handful of undead enemies. When trying to put a list of enemies together I tried to search for monsters tagged as "undead" in this site's search function, and it only gave me results for undead monsters from Mordenkainen's tome? I did not apply this filter, and I don't even have that source book. This seems to be an issue with a few different monster type tags. I tried searching again but including all the books I own in the filter, and it gave me no results, but showed me the Mordenkainen's tome results when I added it into the list. Has anyone else noticed a problem with this? How can we get this fixed?

Ignore the “Monster Tag” field, it’s practically useless. It’s a remnant of how DDBused to do things that they have since abandoned and simply haven’t removed. Just click/tap on the Undead icon at the top of the screen and it’ll filter only undead creatures for you.

That string of icons at the top scrolls left and right and the monster types are in alphabetical order. Undead is all the way the far right.