Sorry for the late reply. For some reason, this is working fine as of now. I don't know why. I made no changes to the pi-hole, router, network, etc. The sites I was using as test cases both work now.
To answer your question, yes, I did change the IP after I configured pi-hole, I set it back to DHCP. I exclusively use DHCP reservations for everything, pi-hole included. The pi-hole IP address has been the same and it never changes. I did go into the pi-hole and correct the IP there.
But as it stands now, everything seems fine.