Pentax SV Shutter Release

I have recently acquired a lovely Penatx SV but there is one issue that bothers me. When I gently press the shutter button the mirror flips up and unless I continue to press the button the shutter will not fire - i.e. I have mirror-lockup. If I continue the press the shutter fires as normal and the mirror returns.

Now, years ago, this is a technique I have occasionally been able to use on some cameras when using slow shutter speed where no mirror-lockup function was available but I can do this every time with this camera.

Now I don't have an issue with this other that wondering if it is an undocumented function with the SV or if it is a warning of an imminent malfunction so may I ask if anyone has had this 'problem' or might have further information on.

Thanks

UPDATE: The camera was diagnosed with a mirror box problem which was subsequently fixd and the camera CLA'd by Robin at Harrow Technical. The shutter release now works flawlessly, the mirror movement is amongst the quietest I've ever heard whilst the film transport is silky smooth.

Thank you for the feedback, and it mirrors my experience of Robin. (Sorry for the unintentional pun...)

We have a KX which had a CLA a few years ago and it operates like new despite being nigh on fourty years old. It's a pity Robin no longer services the 6x7 format cameras though.

Happy shooting with the SV