Logs are stored in ~/.cache/harbour-org.gpodder.sailfish/Logs/ based on some very quick tests with my phone I guess you would have to use the CLI to copy them because sailjail/sandboxing prevents the filebrowser or MTP to access that path, not a lot I can do about that at this stage sorry.
If this is always during driving could it be that you are using a navigation program that is downloading live data (eg. waze)? Or that your car is using your phone as a cellular modem?