Question about MLU on Bronica ETRSi with AE-iii prism

I just received my ETRSi with an AE-III prism.
I mounted it on my tripod and focused on my subject in A mode, then pressed the M button to lock exposure. Flipped up the MLU switch and fired away.
My question is, should the MLU switch back off on it's own, or do I have to do it manually, which I did. I've gone over the manual several times and it doesn't say what should happen after I fire.
I'm not finished with my first roll of film yet, so I would appreciate any input before I go any further.
It's the 40th Anniversary edition if it makes a difference.

Thanks

Hi
The MLU will stay on unless you flip it back after the picture is taken.Peter

And flip it it back after the shot but before winding to the next frame, or it will expose that frame when you flip it back.