I couldn't quite get your code working the way you describe it. I may be missing some point in your program's process. However, assuming your data structure is a hash of arrays (HoA) and you are trying to recover the values from the arrays. Here is what I came up with.

# Compiler directives and Includes
use strict;
use warnings;
use diagnostics;

# Global declarations;

# Constants and pragmas
use constant TRUE      => scalar 1;
use constant FALSE     => scalar 0;

###########################################################;
#main()
{
    my $value1 = 0;
    my $value2 = 0;
    my $ref    = RtnRef();
    my $key    = '';
  
# this line will rtn both the key and the value from the hash   
#    foreach $key (%$ref){
    foreach $key (keys %$ref){            # this works
#        ($value1, $value2)= @$ref{$key}  # @$ref{$key} rtns array ref
        ($value1, $value2)= @{$ref->{$key}} # rtns array vals
    ##do something...
    }

#However when I pass the same $ref to a sub routine
    mysub($ref);


    exit;
} #end main()
############################################################;
sub mysub{
#    my $param = (@_);     # this rtns scalar @_ (== 1))
#    my ($param) = (@_);   # this works ($param = $ref)
    my $param = shift;     # and so does this
    my $key   = '';
    my $value1 = 0;
    my $value2 = 0;
    
#    foreach $key (%$param){
    foreach $key (keys %$param){
#        ($value1, $value2)= @$param{$key}
        ($value1, $value2)= @{$param->{$key}}
        ##do something...
    }
    return;
}
###########################################################;
sub RtnRef{
    my %myhash = ();
    my $key    = 'key1';

    $myhash{'key1'} = [23, 40];
    $myhash{'key2'} = [01, 50];
    $myhash{'key3'} = [99, 22];
    return \%myhash;
}
############################################################;
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