Hi. I wonder if you're aware of anything about Stripe's way of doing things that would make it have trouble with changes to contribution amounts via hook_civicrm_buildAmount implementations.
I've got an issue on github in the "Percentage Price Set Field" extension that's making me think this might be the case.
My guess is that the problem arises because payment info is sent directly to Stripe in one http request, and it's submitted to to CiviCRM in another; and when that civicrm step invokes hook_civicrm_buildAmount to alter the prices, we get an error from Stripe. The error in this example is:
Credit Card: This PaymentIntent's amount could not be updated because it has a status of requires_capture. You may only update the amount of a PaymentIntent with one of the following statuses: requires_payment_method, requires_confirmation, requires_action.
Obviously that github issue is mine to deal with, but in general would you say Stripe is likely to have trouble handling amount changes via hook_civicrm_buildAmount?