In a scrum board, a quick filter that applies a subtraction condition to the filter that is set to the board does not work if this filter is using a field of type label.

No quickfilter selected

"NOT test label" quick filter selected

Board Filter:

project = Bug OR labels = test ORDER BY Rank ASC

Quick Filter:

labels != test

When you click on that quickfilter all issues disappear from the board. You would expect everything but tickets with label=test to remain on the board.

This behaviour seems to be inherited from JIRA JQL itself, as shown below:

When looking for issues where project = Bug you have 6 results (condition A)

When looking for issues where labels = test you have 3 results (condition B)

When looking for A OR B you have 9 results

When simulating a quickfilter to subtract issues "A" ((A OR B) - A), you'll have B as result - Everything good so far

Now, when simulating a quickfilter to subtract issues "B" ((A OR B) - B), you'll have nothing where you'd expect 6 issues as a result