Leaking diapers

[Vaidas]

Hello fellow parents.
We have stumbled into big problem. Almost every time, mine daughter poops into diaper, is goes all over her back. Diapers are her size and fitting good (we are using PAMPERS BABY-DRY NAPPY PATNS 360 FIT size 4). She is ~11kg and 10.5 months. And we having this problem for like 3 weeks now. She is also potty training and does her poop in there, but even after pooping and like after 30 minutes passed, she still poops over diaper and it's all on her back.

Is it normal or something we doing not right? I mean, her butt is all covered with diaper, and I check with running my fingers arounds, and it seems fitting.

Please give some advices, because I don't think it's that normal to change like 3 times a day and all the time she poops, the same happens..