Because of these modules the thread is ending abnormally.

That is not enough information for us to determine anything!

This simple demo does all the steps you've outlined and works.

This is the called .pl file that loads a module and uses it:

#! perl -slw
use strict;
use Time::HiRes qw[ time sleep ];

print 'test.pl started loading';

sub doit {
    print 'doit called';
    for( 1 .. 5 ) {
        print scalar time;
        sleep 1.5;
    }
    print 'doit() finished';
}

print 'test.pl finished loading';
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And this is the program that loads that in a thread:

#! perl -slw
use strict;
use threads;

sub testit {
     do 'test.pl';
}

async {
    print 'before testit()';
    testit();
    print 'after testit()';
    doit();
}->join;
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And this is the result of running it:

[18:40:12.57] C:\test>914924.pl
before testit()
test.pl started loading
test.pl finished loading
after testit()
doit called
1310924420.797
1310924422.29803
1310924423.79802
1310924425.29802
1310924426.79802
doit() finished
[download]

That took me about 45 seconds to write and run. Now how about you make some effort.