Jumpy Frameline

[TR3B]

I have a couple of 50mm LTM lenses I use with a cheap coded adapter I purchased. My problem is that when I mount them it brings up the correct frameline but as I adjust the focus or select a change in aperture, the frameline will change to the 28/90 frameline which makes composition difficult. Can someone tell me if this sounds like an adapter issue or mount problem.

[jaapv]

Adapter problem. The precision of the locking notch or frameline selector extension is insufficient. Filing down the extension slightly will solve the problem.