So, since the intention was clearly to award the bounty, and since that only did not happen due to an honest, simple misunderstanding, is there any way to have that bounty awarded as per the intention of the OP?
Pretty much all things are possible in principle, but this particular outcome would require a Community Manager or SE developer; there are no ...
Unfortunately, there is no recourse for this. The OP has plenty of time to manually award a bounty to the answer they choose. And the help center is very clear on the rules on when a bounty is automatically awarded to an answer.
If the OP wants to award your answer with a bounty, they will need to start another one.