Did you add a debug print statement inside the loop to see what you are passing to basename() in $file? It really works:

$ perl -MFile::Basename -wE 'say basename("foo.psd",".psd")'
foo
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... but passing an undefined value does not:

$ perl -MFile::Basename -wE 'say basename(undef,".psd")'
Use of uninitialized value $_[0] in substitution (s///) at /Users/1nic
+kt/perl5/perlbrew/perls/perl-5.30.0/lib/5.30.0/File/Basename.pm line 
+341.
fileparse(): need a valid pathname at -e line 1.
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