I just spoke to a nice person at Photographer's Formulary inquiring about why a number of things I wanted haven't been available for some time.
I was told that the things out of stock are dependent primarily on Glycin and they've been waiting for the component chemical(s) to make Glycin. (That's one of things I wanted to buy.)
She indicated that the chemistry is expected any day and that Glycin should be available within a week or two. They also have a callback list they can put you on if you want to be notified when it's available.