I have 2 WAN interfaces.  One to Cable (WAN) with a /28, and one to DSL (OPT1) with a /29.  I have no route groups, hence no DG failover.  Have a few LAN rules for policy routing (for our VoIP phones to go over DSL only).  I also have 3 Virtual IP's for WAN only.  2 of them are 1:1 to inside addresses. The 3rd is used for individual port NAT's to different inside addresses.

So my WAN gateway went down – ISP outage.  So the DG was pingable, but no internet connectivity.  I do a manual DG reassignment to OPT1 with no problem.  Eventually our WAN internet came back, and I switched the DG back to WAN.  So when I switched the DG back to WAN, our Virtual IP's were not accessible.  I had to go to the Virtual IP page, do a Save (no changes), and Commit.  They then came back.

A Redmine search comes up with nothing that I can see.  I get matches for "Default Gateway" and "Virtual IP," but the bugs listed don't seem to match my problem.