My 2 Ropiees have swapped hostnames?

Odd situation. I have a RPi4 (hostname ArteraUSB) using its USB connected to a DAC and a RPi2 (hostname ropieee3) attached to a display.

Somehow, the hostnames and the configurations have got swapped, so that the RPi4 is now ropieee3, while the RPi2 has ArteraUSB.

I notice that despite the different hostnames, both are listed as “ropieee” in my router’s network list.

The RPi2 is normally on 24/7, while the RPi4 is only on between 08:00 and 23:00. I did have a powercut last Tuesday, so perhaps the hostnames got swapped when the power was restored?

RPi4 feedback - 80d56966cf738054
Rpi2 feedback - 4b8b8caf861c5e39