Have you ever "worn out" a 1/4" foot?
 

Recently, took my Elna Quilt Pro Queen to get maintenance and also adjusted as the once perfect 1/4" seam from 1/4" foot had "grown". They showed me and explained that the 1/4" foot I got with my machine wiggles on the "ankle" and causes me to have a slightly larger seam. I ended up buying a new 1/4" foot (they had also showed me that my old foot was not totally covering the left side of the feed dogs, which also caused the fabric to move at alight diagonal), but when I got home and held them side-by-side, they look the same.

Has anyone run into this before?

Sounds to me more likely the ankle is worn vs the foot itself. Particularly if the foot wiggles. Check another foot or 3 and see if they wiggle as well. If so, it's the ankle, not the foot.

Can you adjust the position of your needle on your machine?

My thought, too.

I have a Pfaff 1/4" foot with guide, which I absolutely love. I sometimes sew more than a 1/4" and the material fits under the guide. I have to stop doing this and switch feet as I can see where it can, over time, distort the guide. Could this be your problem?

Not with my 1/4" foot on my older Bernina. But I did wear out my walking foot !!!

No, but I did wear out a walking foot. It came apart and no longer stays together. I bought another one.

My 1/4" foot didn't wear out, but it DID cause problems. On mine (for my Janome) there is a small flange that prevents the fabric from moving to the right too far. That had been tweaked out.....was making my seams more than 1/4". I used pliers and tweaked it back.

On some feet there's a metal post that might pop out..it's the part that holds the bottom of the foot in place..I just pop it back in, tap it a few times and then seal it with clear nail polish...works for me...this happened on a serger foot and a 1/4 " foot w/guide...

I also wore out a Walking foot. I purchased a new one a couple yrs. ago as I was afraid they would become obsolete on my 1996 Viking Rose.