Incompatible with Symfony 4+?

A site today showed this error on credit card submission below the Stripe widget:

The "firewall_invalidcsrf_request` service or alias has been removed or inlined when the container was compiled. You should either make it public, or stop using the container directly and use dependency injection instead.

This site was recently updated to D9, and I had a similar issue recently with an older version of the multisite extension., and is the same bug that's addressed in core with dev/core#2037 (closed).

However, this is only happening on one of my D9 sites despite them using identical versions of Symfony.