A USNavy Boeing P-8A has landing around 20:15 CEST in Sigonella after a patrol mission over the Black Sea.
During the flight over the Black Sea the aircraft switched off the ADS-B transponder but we can say with good certainty that the mission took place in front of Romania and Bulgaria.
Most probably the Poseidon has monitored the situation in the Black Sea in front of Odesa to understand the intentions of the Russian fleet regarding a possible landing near the Ukrainian city (which today, after the sinking of the Mockva and the retreat towards the open sea of the Russian fleet seems less imminent than a few days ago).