Once the deposit hits your account it starts earning interest, hold or no hold.
The hold is there just in case the cheque bounces. That has no bearing on whether interest is paid. [If it bounces then sure, the interest will be cancelled--as will the deposit itself.]
That's no different than with paper cheques. At one point the banks had a cutoff time on Fridays, say 5pm. If the bank was open late (TD/CT to 8pm) they'd accept the cheque after the cutoff time but it wouldn't be deposited in their system until Monday (or this weekend on Tuesday.) In that case interest would only start to accrue on the date of deposit. I don't know if it still works that way since I haven't deposited a paper cheque in eons.