Checksums on incoming NMEA strings

[JD1]

This will not be any help but from what I can tell there is nothing that checks the validity of incoming data. My Raymarine chart plotter seems to send corrupted NMEA strings at totally random times - sometimes immediately and sometimes not during 24 hours. Kplex seems to be happy to interpret the corrupted string and eventually the corrupted data will crash SignalK.
I hope you can resolve your issue somehow because your solution might also be used to filter out bad data in my setup.