Strange RA4 light falloff

I've been using the kodak ra4-rt for a while now, but this is new.
A consistent light falloff is appearing on prints that previously did not.
It is cylindrical from the center out, and dissipates at equal proportions.
I've always had minor lens falloff, but was able to do 10-20 % time burning to compensate...now it's up to 60-80%!
It starts after the 1st replenishment, and get progressively worse with each print,
but the centers continue to be properly exposed. Weird.
I've compared the current meter readings to last year, and have ruled out the lamp, and all other associated enlarger mechanics.
Is it possible that the developer is acting proportionally less aggressively with the existing decrease in lens falloff exposure?
Thanks.

The only time this happened to me was when I either had the condensers in the wrong position on my Omega DII-VC head or when the enlarger bulb wasn't positioned correctly.

Seems strange and I can't image how it would be a developer issue.

Have you tried any b&w work with the same setup?

On another note, I don't replenish but use that RT stuff down to 64-65 f with excellent results.

I had one litre in a full bottle that I had ran 15-20 prints, it sat for at least a month, and worked fine when I went to re use it.