The figures, for anyone assembling their own picture. Red flags, in rough order of how much they should worry you: no verifiable address, no batch numbers, prices far under market, vendor-commissioned tests only, pressure toward irreversible payment, and shipping with no temperature control.

Following on from lisa_labSD — and this may be the naive question:

How people are distinguishing a supplier having a bad batch from a supplier on the way out?

SleepDoc_PDX said:

Red flags, in rough order of how much they should worry you: no verifiable address, no batch numbers, prices far under market, vendor-commissioned…

There is a second half to this that has not been said yet. Prices dramatically below market are the strongest single signal, and the reason is arithmetic rather than suspicion. Synthesis, testing, and cold-chain shipping have floors. A price well under the floor means something was skipped, and the two things that get skipped are testing and content.

Reporting back.

Went back through my own correspondence with an earlier supplier and the warning signs were all there in the replies, weeks before the quality changed. I was reading the product and not the behaviour.

hans_munich said:

Prices dramatically below market are the strongest single signal, and the reason is arithmetic rather than suspicion.

Right, and one flattering data point from a group buy is not consistency. Consistency means separate batches, separately commissioned, over months.