Once the fix was released, I waited a few hours before getting in to check things. And, quite honestly, our LabTech server was also being blocked by mbam, so I couldn't get in to really check anything. After about 3 hours when it seemed clear that it wasn't going to solve itself, I found a way into the LabTech server (was able to remote desktop from another device on the same subnet, but couldn't remotely), I was able to get mbam fixed on there. Once I got it fixed, I gave things a few minutes and then found most of the clients were checking in.
I *assumed* if they were checking into LabTech, that mbam probably wasn't causing a problem on them. I spot checked a few and of the online agents they all had v12 or v13 of today's definitions. The agents that weren't showing online had v02 (mostly or exclusively) definitions.
I ran a search for LabTech last checkin >1 hour and <1 day to give me a list of agents that weren't checking in. Some of those had gone offline for other reasons and there was only 5% or so that I needed to go through.
If the agents are checking in, but not getting mbam updates, could sending a restart script to all of them help?