Some banks will provide access to the funds based on the pre-authorization or pending direct deposit, but it is at the banks discretion.

(I have no way of knowing this) If there has been an internal operational change, meaning a deliberate action by the bank. I would guess they are using the pending deposits to allow them to maintain proper reserve balance with the fed overnight. Which they are permitted while funds are in transit. The fed funds rate of 0.25% isn't a lot of interest but it could be a tool they are more actively using given the current economic environment.

Suntrust to me, has always seemed to be a very conservatively operated southeastern regional bank. So it wouldn't surprise me since banks are seeing higher defaults and non payments of loans due to Covid.