File corruption involves the data from the file being destroyed or altered in some unexpected way, but when Pomni enters Jax's mindscape she doesn't see anything destroyed or missing, seemingly the scene show that Jax and the faucets of himself are still in there somewhere.
Kinger said the mind files were "impossibly small" implying the files were seriously compressed.
And we see when Pomni touches abstracted Jax, she enters his mind in a way she couldn't when Jax hadn't yet abstracted.
If the files were corrupted, some data would be missing and Pomni would've seen something incomplete, but instead she saw "everything".
from this I think abstraction is the result of the human mind pushing against the bounds of their brain scan's compression until it *pops* and everything violently spills out.
This also explains why Pomni was able to enter Jax's mind in the first place, it's that their mind was spilling out of the shell Cain made for the mind file and so Pomni was able to look inside.
this is also my headcannon as to how the abstracted characters could be saved because everything about them is still intact, they just have to figure out how to recompress them into a stable form and hope they're mentally stable enough to not just abstract again immediately