Thanks for the info. The port is an unassigned port, as best as I can tell; this just means there's not a specific set application that has it reserved, or is registered to it. Could make our life easier if there was, but there you go...
As to the rest...
Your network rules ID 6 & 7 appear to be incorrectly configured... they should resemble the other "zone" rules so that it will be Allow Out from Any to Zone, then Allow In from Zone to Any. Unless you have a specific reason to set it to Zone to Zone (such as different IP ranges, etc); which I have tried, btw, and it didn't ever work quite right for my system; kept blocking DNS & DHCP stuff that will fall outside of the prescribed Zone. That's all a little off-topic, but I thought I'd mention it.
All the entries are blocked by Rule ID 16, as they are not specifically allowed by the preceding rules. To be honest, I don't know why you are getting those, and if they are related to your having allowed all IGMP and ICMP traffic or not; I have not heard of those protocols being exploited, but you never know... It does seem to oddly coincide, based on the info you provided.
Do you have active antivirus, and is it updated? Have you performed any automatic or manual scans of your system?
What if you remove Rules ID 0 & 1, and reboot... Do the entries continue? You might try that, and let me know.