IP Alias on CARP doesn't work with port forward?

[jasonlitka]

Ok, I've been struggling with occasional spontaneous CARP failovers so I figured I'd try to cut down on the CARP heatbeat traffic by limiting to one CARP IP per interface and switching everything else over to IP Aliases.  According to the page below, they should be interchangeable.

https://doc.pfsense.org/index.php/What_are_Virtual_IP_Addresses%3F

Here's what I did:
1. Tested that everything worked with the CARP IP with VHID 21 (can ping, port forwards work, failover, retest, failback).
2. Edited the VIP and changed the type from CARP to IP Alias and changed the Interface from WAN to WAN-CARP (my base CARP IP for the interface).
3. Hit Apply and verified that the changes sync'd to the backup.
4. Retested as in #1 but I don't receive ICMP responses and port forwards don't work.
5. Undo on step #2, reapply.
6. Retested as in #1 and everything works again.

What am I doing wrong here?

[jasonlitka]

I've figured it out!  Despite looking like everything is fine after hitting apply, the system acts really strangely until you disable CARP and reenable.