ALB returning 400 between services

We started encountering a strange issue with some of our gRPC services not too long ago. Many services call to another to do so sort of work and we started getting 400 (Bad request) responses from the ALB's. One request at a time seems to work, but if we make multiple calls to retrieve a complete set of data (paged) we get the first page, but all other calls fail. We ran a local instance of a service, keeping the other at AWS, and it this case, the call work with no issues. I know the HTTP/2 exploit has been fixed, but could this be causing issues between our services now?

We specifically use the HTTP/2 protocol, not gRPC of the ALB. We are not interested in supporting streaming calls.