Try running it within a Capture::Tiny compartment.

use Capture::Tiny qw( capture );
use Shell::Source;

my $csh;
my( $stdout, $stderr, @result ) = capture {
    $csh = Shell::Source->new(
        shell => "csh", file => "$ENV{Home}/.cshrc"
    );
    $csh->inherit;
};
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(This is an untested suggestion.)