Your picture is identical to the crystallization that I've often seen: The solution collapses, producing a separated liquid and cream. I've known that D-316 is close to the edge of the crystallization-cliff, because I've seen white smudges of the start of crystallization on the bottom of a beaker when mixing it hot (85C). Your test evidently pushed it over the cliff. Congratulations. Actually, this is good news because it gives us a way of stressing a concentrate, and the same test can be done with the final developer. I suspect that the ratio of sodium metaborate to ascorbic acid largely determines vulnerability to crystallization, and the latest developer, 214D, has a lower ratio, so it's hopefully more robust.
Originally Posted by Alan Johnson
Yesterday, I shot and developed an important roll using Delta 400 and 214D. Results are beautiful. Here's an example taken in mediocre indoor lighting at box-speed: