@Devlin_Hugo @WagoKurt
I am experiencing a similar issue on my wago CC100 running node red in docker. I’ve spent the last couple of days trying to solve this but with no positive outcome. Even with only one modbus serial read node and a debugger, after configuring the modbus read node, node red immidiately crash and goes into infinite boot-loop. I finally managed to find the flows.json via FTP and remove the modbus node from the flow and node red started back up on its own, as it should.
Same thing happens (serial only, TCP works fine) with node-red-contrib-serialport and node-red-contrib-modbus.
I’ve found some older info about this being an issue in the past as well, but on raspberry pi. In this case I would assume this is either a firmware or a node issue 
I don’t have any logs available just now. FYI, I have two Wago CC100 installed docker and node-red exactly the same way, both are acting the same way.
Any tips and tricks to solve this?