This is perl 5.32 on fedora 32
Using an older version of File::Copy (2.30) my SSCCE shows that the source file still exists. Perhaps try running this and see what happens?
use strict;
use warnings;
use Test::More tests => 4;
use File::Copy 'move';
# Create a file
my $src = '/tmp/foo.txt';
my $destdir = '/flurble';
open my $tmp, '>', $src or die $!;
print $tmp "Hello, world!\n";
close $tmp;
ok -e $src, "Source file $src exists";
ok ! -d $destdir, "Destination directory $destdir does not exist";
ok ! move ($src, "$destdir/bar.txt"), 'Move fails as expected';
ok -e $src, "Source file $src still exists";
Update: fixed open statement to use the $src variable.