There are many reasons for this.
I think the main reason is bad quality seeds, and in many cases incorrectly identified inactive seeds often are sold.
With HBWR, there are some strains which are inactive which commonly get sold by entheogen suppliers by mistake. Argyreia nervosa var. nervosa is the potent strain. Argyreia nervosa var speciosa is inactive.
The other main reason is improper dosage. SWIM is very experienced with HBWR, and has been lucky enough to never get the inactive variety so far. For SWIM, it’s typical for 1 seed to be enough for effects. But his brother needs 4 seeds. This is of the same batch of seeds. He always needs 4 times as much as SWIM needs.
Another reason is improper preparation. If you swallow the whole seeds as is, they do not get digested and pass through your body and do almost nothing. They need to be ground. It’s best to do an extraction on them.
Another reason is heat. If the seeds are exposed to excessive heat, they will be inactive.
Another reason is age. If the seeds are very old, all the LSH is gone, and only LSA and a few other alkaloids remain. LSA is not really a hallucinogen. If you take LSA without LSH in the mix, all it really does is make you feel lethargic, sleepy, etc., because LSA is primarily a sedative. But when mixed with small amounts of LSH, LSA takes on strong psychedelic qualities, but is still very sedating.
Another reason is possibly chlorine. I think it might be possible that chlorinated water destroys LSH and renders the seeds inactive if they are extracted with it. I’m not sure about this though.
You may remember me as 69Ron. I was suspended years ago for selling bunk products under false pretenses. I try to sneak back from time to time under different names, but unfortunately, the moderators of the DMT-Nexus are infinitely smarter than I am.
If you see me at the waterpark, please say hello. I'll be the delusional 50 something in the American flag Speedo, oiling up his monster guns while responding to imaginary requests for selfies from invisible teenage girls.