> this version ust work fine with Morphos no?

Fab's v0.148 port (and probably his previous ports, too) has display issues with overlay enabled on certain resolutions on graphics cards where MorphOS does support overlay:

https://morph.zone/modules/newbb_plus/viewtopic.php?topic_id=11278&forum=9
https://morph.zone/modules/newbb_plus/viewtopic.php?topic_id=12589&forum=9
https://morph.zone/modules/newbb_plus/viewtopic.php?topic_id=12661&forum=3
https://morph.zone/modules/newbb_plus/viewtopic.php?topic_id=13424&forum=9

Just as with (hopefully) your case, solution is to disable overlay.