@Franhen91 It sounds like for some reason your phone isn't reacting to the change in folding status. For troubleshooting, she can boot her phone in safe mode. If it works properly while booted in safe mode, you know that some 3rd party software is causing it.
To boot in safe mode, https://www.samsung.com/us/support/answer/ANS00062983/
If it still acts up while booted in safe mode, it is probably a hardware issue.