Thanks for the quick reply.
The spreading factor is SF7 which we used to start the join. The first framecount 1 (payload is 51 bytes) is received via MQTT interface of TTN V3.
After the join and first datagram the LoPy4 is instructed to save LoRa state in nvsram which is followed by a deepsleep of ca 16 minutes.
After the wakeup of the deepsleep the LoRa state is restored (join is not needed), measurements are done (ca 2 minutes) and the second LoRa datagram with the new count number is sent off. All datagrams with a higher count as 1 are not received via the MQTT TTN V3 interface.
Without the LoRa nvsram dump, deepsleep and restore all LoRa datagrams are received via the MQTT TTN V3 interface.
LoPy firmware version is 1.20.2.rc10 (Jan 2021).
We will try to get the exact values of SF, channel, etc in a later state and will try to see the raw TTN V3 data of the first datagram and (later) datagrams passing the LoRa gateways used is possible.
If needed we will sent those data later.
Thanks so far.