question

Via Victron Professional you can find a text file with a link to a Venus OS archive.
https://professional.victronenergy.com

You are mixing up something here.
2.81 is the version of Venus OS running on the GX module inside the MultiPlus.
Venus OS updates only automatically if you set it up to do it. The default setting is to check for updates but NOT install them.

2623 is the hardware ID of the MultiPlus and 494 is the FW version on the MultiPlus.
The FW on the MultiPlus will never be updated automatically and there is also no setting to do that.

@Matthias Lange - DE - You are correct, I was confusing the VenusOS version and device firmware. I thought the two were simply different references to the same image. I do see seperate images for device firmware and VenusOS installations looking at the Professional portal now. The thing that's misleading is that the VenusOS version shows under "Firmware" in remote console. Hence, I assumed that updating one contained the image for device firmware and installed both together. Looks like that's incorrect.

That being said, the interesting thing is that everything broke with the VenusOS update. It happened all on the date that it was released and I haven't played with anything in months. ...and yes, I know that I enabled auto update. I didn't set it to install latest release candidate though, so I figured that QA would have been thorough with any release that it auto updated to.

@mvader (Victron Energy) - Thank you. I will get remote support enabled and respond to the email. For now, I figured a few things. In an attempt to get things working right again, I reverted to 2.80 and allowed the GX to auto update to 2.81 again. When it completed this time, I noticed that it was running at 50Hz! As stated in my original post, I checked this yesterday when I noted that the microwave and espresso machine sounded like they were using a dirty sine wave (a space heater we have wasn't working either). It said it was at 60Hz at that time, but I think the software was lying to me after the update! As soon as I downloaded the configs today and rebuilt them from scratch, as using my old configs was not working in Remote VE Configure, everything has returned to normal with the exception of the VRM portal, which still shows "Too busy. Realtime link is disabled", and shows that whether connected via Ethernet or WiFi, and WiFi was tried with home network and WiFi hotspot on a phone.

tldr;

• Reverted to 2.80 and allowed to take 2.81 again. Lost frequency setting and many others.
• Original 2.81 update showed running @ 60Hz, but all inductive loads behaved like 50Hz.
• After 2nd 2.81 update and rebuilding config from scratch, shows running at 60Hz and loads behave/sound like normal.
• VRM is still not working right. Never goes to realtime. Always shows "Too busy. Realtime link is disabled." Never happened ever before prior to Jan 31 v2.80 update.

nanopi resources are healthy:

Mem: 309516K used, 200808K free, 1852K shrd, 12708K buff, 90644K cached

CPU: 1% usr 1% sys 0% nic 96% idle 0% io 0% irq 0% sirq

Load average: 0.09 0.26 0.37 2/305 6400

Haven't looked at logs yet. I'll enable remote support and respond to the email so you can.

Update: mvader reached out to me and requested remote access. He logged into my MultiPlus II GX and saw that I had in fact installed GuiMods. I read that GuiMods doesn't survive update, but I didn't know that it could interfere with an installation during update. Turns out that this was the case. It caused the issues that were stated above, somehow....and caused the issues with the lag I was experiencing.

I haven't been using GuiMods, as I was never able to get the GeneratorConnector to work anyway, since I had to build a custom assistant for it and use two device's relays to get remote start to work with my generator (Predator 9500), since it doesn't use a control board and needs seperate start/stop circuits. When mvader looked into dbus on my install, he saw a ton of messages tossing errors around from non-Victron interfaces.

Later, I looked at the dbus output as well and saw the same. I attempted to uninstall GuiMods to fix this, but was unsuccessful with all attempts:

Tried the following:

• Removed the hooks (/data/rc*.local) and downgraded/upgraded to 2.81. Still saw same dbus output.
• Ran all installed GuiMods setup scripts manually and used their uninstall option. Downgraded/upgraded to 2.81. Still same output.
• Ran "blind install" of SetupHelper and used it to upgrade/reinstall all scripts I originally installed, then uninstall and downgrade/upgrade to 2.81. Still same output.

Finally, I setted on factory reset, covered here:

https://www.victronenergy.com/media/pg/CCGX/en/factory-reset.html

After factory reset and reconfiguring, latency has returned to normal in VRM Portal.

Thanks for your help @mvader (Victron Energy) ! Class A customer service and support. Never had a customer service experience that was quicker and more involved. Very much appreciated.