Image Stabilization doesn't work with third party lenses

The Image Stabilization (IS) recently stopped working on my OM-D EM 5 MkII. Whenever I mount one of my Samyangs (7.5mm fisheye & 12mm) and IS is activated, the display moves all over the place as if the IS is making the sensor jump around. It's doing the exact opposite of what the IS is supposed to do. The lenses work fine with IS turned off. This problem doesn't coincide with a firmware upgrade.

Has anyone else run into this problem?

Thanks

Did you enter the lens focal length into the camera?

The IS won't know how much to compensate if it does not know the focal length of the lens.

I agree with Gary Nakayama. There is a mismatch between what the camera thinks the focal length of the lens is and what it really is.

Manual lenses are nice & cheap but to me a PITA to use when you have to temember to reset the IS everytime you use one. I did pick up a cheap Samyang 7.5mm FE long ago but it’s been forever since I used it and recently picked up the M. Zuiko 8mm f1.8 FE. Wherever that Samyang is, is where it’ll most likely stay permanently.