... I also included: use strict; use warnings;

Really?  With use strict it should've stopped working

#!/usr/bin/perl
use strict;
use warnings;

our $pax_1 = "foo";
my $plus = 1;
my $name = "pax_$plus";
my $paxing = ${$name};

print "$paxing\n";

__END__
Can't use string ("pax_1") as a SCALAR ref while "strict refs" in use 
+at ./880063.pl line 8.
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unless you also disable strict refs, e.g. as follows

#!/usr/bin/perl
use strict;
use warnings;

our $pax_1 = "foo";
my $plus = 1;
my $name = "pax_$plus";
my $paxing;
{   no strict 'refs';
    $paxing = ${$name};
}

print "$paxing\n";  # "foo"
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