Pfsync rules dissapear
I have two pfsense FW on the latest version - I'm running snort and pfblocker and when the primary attempts to sync with the backup through the dedicated pfsync interface the rules on that interface magically disappear and the sync fails. I have increased the max table entries to 60,000,000 from the default of 6,000,000 with the same result.
The problem exists even if I disable pfblocker on the backup or even on both pfsenses. It's something with the sync function that always disables the pfsync interface FW rules which than fails the sync.
Your interfaces are not assigned identically. The rule isn't disappearing, it's being put on whatever OPT interface the primary believes is the sync interface.
Check your assignments on the secondary and fix them.