At the moment, there are a number of small aircraft that get pretty “weird” on approach. As quoted from one of the FSReborn developers (who made the excellent S4), there are issues with the SU9 convection thermal depiction, which apparently is going to be toned-down by Asobo in SU10 .
I don’t own the Twotter, so what you mentioned might not be directly related to the above, but it might be worth giving her another go in SU10 .