Tested with 6.15 and 6.19 - after "/system shutdown" the ethernet bypass is not activated, power has to be physically disconnected. I can hear the relay clicks on power up/down and while rebooting, but not when system is halted (even though ethernet ports are disabled, no more link).

The bypass are hardware feature, not matter what RouterOS version have.

The bypass switch are put firmly on "1" position?

The bypass are from port 11 to 12.

Yes, I understand how it works. The relay is activated by software (some GPIO pin), not wired permanently to power supply - as it clicks during reboot. So it should only be active (disable bypass, enable normal function of ports 11 and 12) while ROS is running properly (not if halted by "/system shutdown").