Problems with Payment Bypass Link?

Our weekly matches are always set up requiring prepayment online at registration time. Occasionally, I’ll send a bypass payment (aka “free link”) url to some of the workers for one of our matches. To my knowledge, they have all worked seemlessly except for one particular worker. For me (and other workers that have used it), the free link leads to an identical registration page but without the payment associated fields (credit card, potential discounts, etc) as you would expect. However, for one particular worker, he tells me the free link still shows all of the relevant payment fields on the screen, rather than the payment-field-free registration page the rest of us see. Is there some problem that could lead to this behavior? He happens to be running Safari 14.1.2 on Mojave MacOS.