'Neighbour' mulit language offline maps not displayed

I just downloaded the many offline maps for Germany from OpenAndroMaps. They come in the mapsforge v4 format with multi language support. If I select e.g. Hamburg and scroll to the map's edge, the neighbour maps (Niedersachsen, Schleswig-Holstein) are not loaded.

Of course the automatic loading settings for Vector maps (and LoMaps) is activated.

As I also still have the v3 maps for Australia on my smartphone, I also tested the same scenario. There all maps are correctly loaded, even if I scroll to the next state.

I searched the web for already existing reports and further hints in the FAQ, but could only find an entry on OpenAndroMaps https://www.openandromaps.org/oam-forums/topic/locus-pro-automatisccher-kartenwechsel.

I use Locus Pro v 3.37.2 if that is somehow important.

The obvious workaround is to use v3 maps, but as OpenAndroMaps switches completely to v4, I'd rather have that known as an issue for the Devs ;-)