The Norwegian lake Mjøsa is not drawn for some zoom values. It looks fine for zoom >= 10, but disappears for values <= 9. Other smaller lakes can be seen, but Mjøsa, the largest in Norway is missing. Logged in or not does matter.
It can be seen on https://maps.wikimedia.org/#9/60.6826/10.9685
The town of Hamar is at the lake.
This problem is similar to T215641
If this is some kind of cashing problem it would be nice to be able to somehow be able to force a refresh of that feature, e.g. using its Wikidata tag.