Proto: fix #2084

Context

This is a tentative fix for #2084 (closed)

Also fixes issue #2554 (closed)

Manually testing the MR

dune run src/proto_alpha/lib_protocol/test/integration/consensus

Checklist

• Document the interface of any function added or modified (see the coding guidelines)
• Document any change to the user interface, including configuration parameters (see node configuration)
• Provide automatic testing (see the testing guide).
• For new features and bug fixes, add an item in the appropriate changelog (docs/protocols/alpha.rst for the protocol and the environment, CHANGES.rst at the root of the repository for everything else).