I migrated my existing devices (OTA and ABP) from v2 to v3 and these work fine.
Today I created a new ABP device (OTA works fine for new devices) but for some reason the stack always sends a lot (about 50 bytes) of downlink data:
11:39:23.223 → Data Received: 0503D2AD84060703184F84500704E85684500705B85E84500706886684500707586E84500351FF00030805
This is not visible in the application console, only the uplink data is shown, but the downlink counter is increasing.
Also my gateway shows the unwanted downlink:
I made the node configurable for both OTA and ABP.
So it is running the same (LMIC) code in both modes and only ABP shows this behaviour.