ignored unrecognised input when compiling with a plugin

Summary

When I compile a package with ghc-tags-plugin enabled, e.g. passing the following options (one will need to modify it depending on your system):

package io-classes
  ghc-options: -package-db=/home/coot/.local/state/cabal/store/ghc-9.6.4/package.db/
               -plugin-package=ghc-tags-plugin-0.6.1.0
               -fplugin=Plugin.GhcTags
               -fplugin-opt=Plugin.GhcTags:../tags

I am getting the following warnings:

Warning: ignoring unrecognised input `/home/coot/clients/iog/io-sim/dist-newstyle/build/x86_64-linux/ghc-9.6.4/io-classes-1.4.1.0/build/Control/Concurrent/Class/M
onadMVar.dyn_o'
...

It doesn't really matter what package I try to compile; I haven't tried to use any other plugin, but I don't get that warning when I disable the ghc-tags-plugin.

Steps to reproduce

Given above. To install ghc-tags-plugin follow instruction in the readme

Expected behavior

No warning.

Environment

• GHC version used: ghc-9.6.4

Optional:

• Operating System: Linux
• System Architecture: x86_64