Hi @sonyxa2, in order to fix the recurring error
enablefilecrypto_failed?
my preference on upgrade is to Fresh install.
This Build feedback for v3.7 thread does not seem the best place to continue, perhaps if you open a support thread on the subject of fixing this error would be better. ??
In another thread your might try to lay out the update history.
I cannot tell whether the story is? Slot A took the Upgrade to a15 (although an error was mentioned), you managed one update only to slot B, and now slot A resists update.
In the natural course next (if you Upgrade because updates are failing) you will be trying to force Upgrade to slot A. Whatever you decide to do, just in case storage failure (eMMC) might be the issue, a good backup is the priority right now.