I'm on 10.47.7
I have created a new simple tag structure as follows. Each tag has one note in and the tag names have spaces
When I click the blue lozenge and then select 'include sub tags' method it works fine'. The results are as expected.
1) However, when I try this on a real tag I have, which has >100 sub tags, and even sub sub tags, I get zero results!
2) I tried it on an existing parent that had 11 subtags (no sub sub tags) and a total of 36 notes in all tags and it worked fine.
3) I then tried it on an existing tag which had which had 70 subtags (no sub sub tags) and it found zero results.
Strangely, whilst clicking the blue lozenge and then selecting 'include sub tags' in item 2 above works, if I right click the tag in the left sidebar and select 'filter with sub tags', I get no results?! I believe this does indeed do an AND as per this