Focus Oscillation in K3 iii?

I have the K3iii (updated to the latest firmware) and purchased the new 16-50 PLM and I had similar trouble with focus consistency.

I initially thought the problem was due to shooting at wide apertures, but I took numerous pictures under normal, along with fairly controlled, circumstances. I used both AF S and AF C and in different configurations (spot, as well as various area sizes). I also carefully used the autofocus calibration (indoors) and +2 generally worked well for pictures (well, indoors) when focus properly worked.  I also used back button focus and shot in single shot and also high and medium speeds.

Unfortunately, focus often would be off by several inches to several feet. I found I was missing focus about 50% of the time. Focus indoors was more consistent. Overall, though, the lens was not workable. And, I took pictures with movement and with the subject standing still.

Optically the 16-50 PLM was excellent and appeared to be well-centered (and was sharper than my D FA 24-70), but focusing simply was not reliable.

I do not have this problem with my other lenses. I also own a K5ii, K3, K1 and K1ii and usually shoot mixed martial arts and Brazilian Jiu Jitsu events. I also shoot in manual mode, RAW. So, I am pretty well versed in using my cameras in low light and at wide apertures.

I ended up returning the 16-50 PLM. Perhaps I will give another copy a try, but I think I will hold off for now.

I actually purchased the K3iii shortly after it was released last year and had focusing and file corruption issues (I had read posts by others who had similar problems). I returned the K3iii and hoped that future firmware updates would solve the issues. I took a chance and re-purchased the K3iii a few months ago and all is well. I really enjoy using the camera, especially at competitions and tournaments and was hopeful I could use the 16-50 PLM. Oh well. Perhaps next time.