Old developer turns film black in clip test -- but are other aspects of a "good negative" affected by developer age?

I developed three tankfuls of film this weekend, in old D-76.

Two tanks came out with sensible contrast, 0.62 CI aim and actual 5222 but then Sunday a run of Panatomic-X came very short of aim. Fortunately I aimed very high so the result, though thin, should br printable.

I had maybe one ounce stock left in one bottle that I added to seven ounces stock from another, both bottles had been drawn from the day before with good outcome.

I will do another test to see but lately it’s been hard for me to hit 0.62 CI