In that case, the issue may be the location of (potentially multiple copies of) modules and the order in which perl is finding them from @INC.

In the following, note how '.' moves from $INC[-1] to $INC[0] (compare with my earlier perl -V output):

#!/usr/bin/env perl -l

use strict;
use warnings;

BEGIN { print "BEFORE use lib: @INC[0, -1]" }
use lib '.';
BEGIN { print "AFTER use lib:  @INC[0, -1]" }
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Output:

BEFORE use lib: /Users/ken/local/lib/perl .
AFTER use lib:  . /Users/ken/perl5/perlbrew/perls/perl-5.18.1t/lib/5.1
+8.1
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