0 Search Results Counter decreasing


We implemented the 0 Search Results according to the FAQ and it worked well out of the box.
A few days after the implementation, we saw that the 0 Search Results Counter is not only increasing, but also decreasing at some point.

We didn’t expect that behaviour, so it raised some questions:

.) Does Matomo remove keywords from the 0 Search Results if a later search delivers results?
.) If yes, is that behaviour configurable in terms of “As soon as one search result equals zero, the keyword will be added to the 0 Search Results keyword list and stays there, even if later searches deliver some results?”
.) Or is this probably an error with our implementation?

I appreciate any help or hints that could help me out!
Thanks a lot!