Storage [Q] Problem with the partitions on TabPRO?

I own a Galaxy Tab PRO 10.1" Wifi (SM-T520).

I have the stock ROM, rooted and with TWRP. And SDfix...
I have tried fat32 and ext4 on MicroSD, and without MicroSD. No difference.

I cannot boot any custom rom (Stuck at Samsung logo). Sometimes when I try to install a rom, it fails, or reboots TWRP.
I also encountered problem when trying to restore a nandroid. No DATA partition can be written to, restore fails. (after reboot recovery, its no problem to restore)

Angry Birds Epic does not work. It stops at "Loading Levels", and sometimes it fails to start, and says its not installed.
Spotify says that that it cannot be used because it has no storage.

I can access the partitions, but they are not writable. A reboot is getting the internal/external SD to be writabe again.

So, what is the problem with the partitions on TabPRO? or is it the Samsung android rom thats the problem?
Can it be fixed?

Device: SGS4
ROM: Imperium v10
Kernel: Googy Max 3
Theme: GSS5
Recovery: TWRP
Baseband: NG8

Device: Samsung Galaxy TabPRO
ROM: GigaWatts Pro 3.0
Kernel: Stock
Codename: SM-T520
Recovery: TWRP
Baseband: AND1