That's it!
In a linear average it should have dropped by .02 only.
You may have kicked out a score of 40 or 81 (*), as .05 x 500 = 25 (*) shots difference.
(*) with quite a rounding error.
Now a steep fall will follow, shaving off all the lesser good scores of the past,
and then back to sour waiting for those sub-30s...
You can check saturation by playing a ranked round above the average - e.g. a 34. If the average drops regardless, you have the proof.
If it rises, I have a problem ;)