Ahh…i found the following post which seems to have solved the problem - at least so far.
Openhab resets serial connection with my gateway every couple seconds - #5 by pawlo999
I disabled debug messages on the gateway, and so far the total death has not occurred 
.
However there is still some kind of issue with random dropouts, where the bridge stays online but the nodes appear to be lost… the log entry reflecting this is …
2021-03-26 07:54:05.468 [DEBUG] [rs.internal.gateway.MySensorsGateway] - Node 102 found in gateway
2021-03-26 07:54:05.468 [DEBUG] [rs.internal.gateway.MySensorsGateway] - Child 4 not present in node 102