I have been finding it difficult to flare the Airfoillabs Cessna 172 on landing. The aircraft would either plant it's nose down firmly, or pitch up far too much. Holding it at the correct controlled angle was an issue.
Apparently it's a common problem with the interaction between wing the downwash and the horizontal tail. A single component of the calculations required was missed. The fix is due in the next major update, probably 11.1.