You passed an empty string for 'payment_method'.
Since upgrading to Stripe 6.7.9 we have received two reports from people who say they get an "invalid request" error when they try to make a contribution or pay for a paid event.
In both cases, these reports line up with the following messages in the civicrm_stripe_paymentintent
table:
req_xxxx;You passed an empty string for 'payment_method'. We assume empty values are an attempt to unset a parameter; however 'payment_method' cannot be unset. You should remove 'payment_method' from your request or supply a non-empty value.;...
(There is also an error in ConfigAndLog about the string being truncated but that's not the cause of the stripe problem).
It doesn't happen on all requests. I'm still trying to zero in on how to replicate.