When I use Leaflet, everything is okay!
Changing back to Google Maps, all caches are shown - not only the PQs.
Tried the same with MS Edge.
Same problem, changing to Leaflet, everything is okay, changing back to Google Maps and reload, everything is okay, too.
Then I closed Edge, started again and: Now it works!!!
Then I closed Firefox (I usually use this browser), started again: No change! Google Maps doesn't show the PQ.
Seems to be a mystery...