Searching posts not working when specific taxonomy not set

[quickdry]

this will use the "Tag" taxonomy as the example

If the tag dropdown is set to a specific Tag, and search is done via free entry text, the get post query works as expected, and finds all posts with "Tag" and searched for text.

If the Tag dropdown is set to "All Tags" and search is done via free entry text, the get post query has a (0=1) inserted in the where clause where the taxonomy type would be (if this (0=1) is removed from the query, the query proceeds properly.)

(Categories work normally when set to "All categories", but from what I could understand in the code, these are unmodified from standard behaviour)