Generating byte code from interface files leads to "silly extra arguments" in CorePrep

When a compiler with assertions enabled I see a lot of warnings of the form:

WARNING:
  CorePrep: silly extra arguments:
  $dm**>
  Call stack:
      CallStack (from HasCallStack):
        warnPprTrace, called at compiler/GHC/CoreToStg/Prep.hs:674:21 in ghc:GHC.CoreToStg.Prep

When generating byte code from the interface files.

How serious is this warning?

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