Samsung Galaxy S9: Cannot change /data to ext3 - mke2fs: Error 134

Before installing e with the easy installer (Linux), I have unlocked the OEM mode, directly reboot to download mode, loaded the latest TWRP and made a backup of the whole firmware (despite /data) to an usb stick.
After that, I have rebooted and got an error message in an language I don’t understand (maybe polnish?).
Because of that, I have rebooted into the original recovery and have done a factory reset.
Then, I used the easy installer to install e.

The step to unlock OEM mode didn’t work for me because the setting was not visible.
But because I have unlocked it before, I have ignored that and continued.

Everything went fine - until I should change the file system on /data to ext3:
There, the error message

mke2fs -t ext3 -m 0 /dev/block/sda25 process ended with ERROR: 134
Unable to wipe Data.
Error changing file system.


I have continued (resizing the partition did work) and get a booting e-os. Yeah!

Then, I restart into the recovery and try to change the partition layout again - no success.

Does anyone know if this is a problem for continuing using (and updating) e on my Galaxy S9?

How to fix the error with the file system change?

I’ve tested other file systems and formatting with exfat and ext4 works.
AFAIK ext4 is compatible to ext3, so there shouldn’t be any problem, should it?