Thank you, Steve, you somewhat pointed me in the right direction.
The location of the events are located here:
Applications and Services Logs > Microsoft > Windows > DHCP-Server
I checked and I couldn't find the culprit, but there's a DHCP server log file here:
The log file revealed the following error while a client was asking for an IP and the OpenVPN tunnel was on:
"Packet dropped because of Client ID hash has mismatch or standby server"
Upon further search, it turns out that the Active Directory DHCP server on Site A was trying to contact an AD DHCP server on Site B that once was part of the AD Domain of Site A, but since was removed from, but some more cleanup was necessary on AD Site A to make it stop trying to contact that orphaned AD Domain Controller. The issue has been resolved, all clients are able to obtain IP #'s from Site A.
Thanks so much for the hint.
Stay safe my friends.