Welcome to iRV2.
Have you checked for debris along the slide seal flange? A friend had similar problems caused by a pine cone.
Have you checked under the slide floor where it runs over the interior floor?
Most slides have a roller (s) under the slide's leading edge; to support it as it moves, if that roller is loose or misaligned that could push the slide up and out at the top.
If the slide is mounted too high, then the roof of the slide can bind on the top frame of the wall opening and stop the top early as it retracts.
EDIT: Adding more info about your RV, ; year, make and model , will help other members give answers.
99DSDP 3884, Freightliner, XC, CAT 3126B, 300 HP /ALLISON 3060
2000 Caravan toad, Remco & Blue Ox.