Searching for a tag that doesn't exist (the EE report) or for a substring of a tag that does exist can produce 500 errors from the server. We made a fix (that I can't find now) after the initial meta report but it did not fix the whole problem. This needs more investigation.
meta:291242 (and another reproducer Also https://electrical.codidact.com/posts/291745
Not fully characterized.
Searching for a tag that doesn't exist (the EE report) or for a substring of a tag that does exist can produce 500 errors from the server. We made a fix (that I can't find now) after the initial meta report but it did not fix the whole problem. This needs more investigation.