Bosch 3000, B450 periodically loses connection to its cellular B443 card

[mb2]

I have a self installed Bosch 3000 alarm system that has an ethernet card and the B450/B443 cellular communicator interface.
The system generally works fine and I get simultaneous alerts from both interfaces via the RSC+ cloud app.

However approximately every 3-4 months the B450 loses its ability to talk to the B443 cellular card.
The symptoms are absence of arm/disarm RSC+ alerts from the cellular interface, whilst I continue to get alerts from the ethernet interface.
Sometimes I see a cryptic message such as "push mod fail" or something like that which is presumably the Bosch 3000 complaining about its inability to send a message via the cellular interface.

For a day or so the LED indicators look normal then the B450 and the B443 set their blue status LEDs to indicate a communications failure.
I can see from the cellular provider logs that the B443 is still talking to the cellular network.

I can connect to the panel via the A-Link Plus software and the working ethernet interface. It lists the ethernet interface as "Cloud online" and the B450/B443 module as being "Cloud offline".
The only way to get the B450 and B443 talking to each other again is to completely power cycle the whole system.

So is this a firmware bug in the 3000 panel or the B450 interface?
The 3000 panel clearly knows something is wrong but doesn't know how to fix it. Shouldn't there be a watchdog that reboots modules that have lost the plot?

[mb2]

Some more information, the exact messages I see are "PUSH FAIL MOD 2" and "PUSH RES. MOD 2" which presumably refers to module 2 which is the B450. The ethernet interface is the first module.

[joelau007]

With both B426-M and B450/B443, have you somehow exceeded the SDI2 power limit ?