Towards the top of the Unum Tower I was just about to free the last Veiled Ostron when I realized I couldn't switch back to the operator. As such, I couldn't remove the mask. I proceeded up the tower hoping my ability would re-enable, but it didn't. I was thus unable to activate the two crystals and lost the timed segment. After the reset I was still unable to access Transference.
See screenshots here: https://imgur.com/a/ECTNVHB
Whenever I press the ability key [5] it says "Ability Not Ready" despite working fine up until the last Ostron.