Blank film, have checked usual suspects

[Melvin J Bramley]

When in doubt, dump everything and start again.
New film, fresh chemistry.

 

[koraks]

The thought that refrigeration may have resulted in some changes should be considered.

Chilling developer doesn't kill it. If things drop out of solution, (1) you would surely have noticed and (2) it mostly goes back into solution as the developer warms up to process temperature anyway.

 

[Agulliver]

I would have thought that chilling developer and other photochemicals would potentially slow down their degradation. I don't recall any of the instructions for developers that I've used down the years advising not to chill or refrigerate the solutions. As @koraks says, one would normally expect any solids to redissolve.

It's not something I do, though I bet plenty of people down the decades have kept developer solutions in unheated basements, sheds, garages, attics etc.