easy
your far lower wing loading requires far lower speed to land
the wing flys to a very low speed then the loss of lift is quick as you increase AOA for th 3 pointer.
example
I had a electric Cub total weight was 3 lbs very light
wheel landings were always a breeze
but
if I tried to slowly rotae to a 3 pointer - it would "dump at the 3 point attitude
My Funtana (90) does exactly the same thing
your old trainer would rotate and land before speed was very low.
Typical wing loading (?) on some trainers is pretty high -compared against slow speed 3D models
On My many years old Seniorita tho ,it is extremely low -it weighs under 4 lbs and is 800+ sq inches
it will also settle quickly if over rotated.
I keep it around for old times sake -to let new guys try their hand at it etc.. Further -- my flat airfoil foamies with wing loadings of 3 ounces to the foot -- same thing - they fly up to almost a dead stop -then just --drop
If you bend the foil to an undercambered foil (curved flat plate) -- same thing
maybe the speed is different -but is too slow to see any difference.
Trainer airfoils are simply a carry over from full scale appearances -in my bok. One of the best trainers I have flown--is the large Diablotin -with 40 ZDZ - it simply will crawl along and land like a feather - the airfoil is symmetrical and extremely thick- so lift wize it is quite compromised -- it can be rotated to higher AOA with no sudden break out.