You included the use Data::Dump qw[ pp ]; from my code into yours;

but then you threw away the pp \%newhash; which I used to produce the output:

C:\test>junk
 { key1 => "val5,val6,val7,val8,val9", key2 => "val3" }
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If, after populating your two hashes: %h1 & %h2, you used the same tool to dump them to the screen before trying to use them:

pp \%h1;
pp \%h2;
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You could check whether you have populated them correctly.