Hello mje

You could use File::Slurper which does not have this problem. Source of information Bug 1425077 - Deprecated use of Slurp.

I quote from the reference above:

The best thing to do would be to backport the upstream patch that make
+s Bugzilla use File::Slurper (which doesn't have the issue) instead o
+f File::Slurp.
[download]

I have not tested, so I can not say 100% will work but you can update us after applying it. :)

Hope this helps, BR