Are you sure it is magnetized ? If it were, then switching the machine off should not solve the problem.

The 1 point relay is activated via the playfield switches. If it is staying on, than means there's a switch on the playfield that is shorted. There is a set of contacts on the 1 point relay than "hold" the coil "on". These need to be gapped correctly or the relay will appear to stay energized.

If it is magnetized, it would stay "on" all the time.

I would try a simple test.

Fire up the game. Push the 1 point relay "on". Does it stay energized ?

YES = The replay needs to be adjusted.
NO = A Playfield switch is getting stuck, shorting out the switch. Go through each 1 point switch.