Odd GHCi behavior

I just saw this rather odd behavior in GHCi (6.0.1, RedHat 9.0):

...
Skipping  Util.List        ( ../../libraries/Util/List.hs, 
../../libraries/Util/List.o )
...

Failed to load interface for `Util.List':
    Could not find interface file for `Util.List'
    (use -v to see a list of the files searched for)
Failed, modules loaded: ..., Util.List, ...

Doing a big old clean, --make, and then GHCi solved the problem.  But what 
could cause this kind of behavior?  (I can't reproduce it, sorry.)

A

-- 
Andy Moran                                         Ph. (503) 626 6616, x113
Galois Connections Inc.                                 Fax. (503) 350 0833
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