WR21 connecting wrong APN after SIM failover

We have WR21-002B-DE1-SH unit with Cellient MPL200 module in a sea vessel. The vessel is traveling between two countries. We have two SIMs connected on WR21, one for each country (different ISPs). The failover works to one direction, but when the vessel is returning, it tries to connect with wrong APN (the APN from secondary SIM), when connecting back to the original network (SIM1).
We have tested the SIM failover at our office with two different ISP SIMs and it works, but on the sea vessel it doesn’t change to the correct APN, when changing back from SIM2 to SIM1. What might cause this?