The Jargon File (version 4.4.7, 29 Dec 2003):

lossage
 /los'@j/, n.

    [very common] The result of a bug or malfunction. This is a mass or
    collective noun. ?What a loss!? and ?What lossage!? are nearly synonymous.
    The former is slightly more particular to the speaker's present
    circumstances; the latter implies a continuing lose of which the speaker
    is currently a victim. Thus (for example) a temporary hardware failure is a
    loss, but bugs in an important tool (like a compiler) are serious lossage.


The Free On-line Dictionary of Computing (30 December 2018):

lossage

    /los'*j/ The result of a bug or malfunction.  This
   is a mass or collective noun.  "What a loss!" and "What
   lossage!"  are nearly synonymous.  The former is slightly more
   particular to the speaker's present circumstances; the latter
   implies a continuing lose of which the speaker is currently
   a victim.  Thus (for example) a temporary hardware failure is
   a loss, but bugs in an important tool (like a compiler) are
   serious lossage.

   [Jargon File]

   (1995-04-19)