@SteveITS I can't explain it either. I didn't add or remove any rules. The only change was to upgrade from version 23 to 24.09, then I began showing block logs on a rule that was set up as a pass rule for IGMP traffic on one interface only.
I then tried a bunch of options to get the rule to work, eventually deleting the rule and creating a new identical rule. Then the phantom deleted and new rule were both blocking traffic, even though they were pass rules. I had the IP Option checked early on in one of the troubleshooting steps I was going through.
The only thing that has seemed to fix it was to change the existing pass rule source from the subnet 10.10.45.0/24 to any, and then reboot the router again (I rebooted previously too with no change in behavior).
Once I rebooted, the blocked traffic was resolved, so I changed the source from any back to the subnet. Now everything is working. I'm baffled, but it's solved and I can't repeat it, which isn't very helpful to anyone.
I appreciate the help with the articles. If there is any way I can try and provide additional details, I'd be happy to.