Hello. I’m having the same issue, as seen by the first 2 images, and r.DOF.Kernel.MaxForegroundRadius 0 did not fix the issue, as you can see in the below 2 images.
I’m rendering an image sequence, and the issue seems to stem, at least on my end, from whichever object or objects are closer to the camera. As the camera pulls back from the terrarrium, the issue goes away. Once it’s all the way at the end, once it seems far enough “away” from the other objects. As you can see in the final image. Final link is the image sequence rendered as an .mp4 on YouTube. You can see towards the end, as the point of focus animates from the terrarium to the chair that the DOF goes completely nuts, so perhaps it’s somehow also related to the animated focal point.
hope this helps. I’m new.