I have seen this as well. I've been using my XTOL replenished so I had thought it might be buildup of some residue after many rolls, so I filtered it out. Have not noticed any effects one way or another from filtering.Both of my prior batches of XTOL have done this at room temperature
Your developer looks really interesting. I've been watching this thread over the last few months and have gradually acquired all the ingredients. The last of my XTOL is gone now, so I'm going to be making up a batch of this formula to try it out.
So, looks like some great work you've done. Thank you for sharing!