I think it might also be related to the bug that the plane does not get the altitude correct when the standard pressure is set. When I do that, the plane levels of at for example 19800 feet instead of FL200. When I set a vertical speed to further climb it will climb a little bit and then it also registers the cruise (you can see the speed target change from 180 to (I think) 220 or 240.
Weird that this wasn’t found during testing (assuming this thing has been tested by others than the dev)