For testing, one can also use the ttnctl command line tool to set the frame counter to some specific value, and then make the test node start with that value too, rather than starting at zero. This might also be needed when the difference between device and TTN exceeds MAX_FCNT_GAP, being 16,384. (But when adhering to the Fair Access Policy that should only happen when erroneously resetting the frame counters in TTN Console.)
Just for future reference: what is the correct setting (for your LMIC device)? (I’d assume 32 bits, which is also the default in TTN Console.)