There are many anomalies in your OP code.

For example, you have many blocks of code like this:

                unless (exists $$dataref{$eid}{"ALL"}{"MatchesPeopleEn
+ded"}){
                     my %a :shared;
                     $$dataref{$sid}{"ALL"}{"MatchesEnded"}=\%a;
                }
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Note that you are testing exists $$dataref{$eid}{"ALL"}{"MatchesPeopleEnded"})

But are assigning to $$dataref{$sid}{"ALL"}{"MatchesEnded"}=\%a;

That probably explains your immediate problem. However, there are further anomalies.

For example, why are you assigning references to shared hashes to a bunch of variables that you subsequently are using as integers:

            $$dataref{$sid}{"ALL"}{"MatchesStarted"}++;
            $$dataref{$sid}{"ALL"}{"MatchesPeopleStarted"} += $tn;
            $$dataref{$sid}{$whichco}{"MatchesPeopleStarted"} += $tn;
            $$dataref{$sid}{$whichco}{"MatchesStarted"}++;
            $$dataref{$eid}{"ALL"}{"MatchesEnded"}++;
            $$dataref{$eid}{"ALL"}{"MatchesPeopleEnded"} += $tn;
            $$dataref{$eid}{$whichco}{"MatchesPeopleEnded"} += $tn;
            $$dataref{$eid}{$whichco}{"MatchesEnded"}++;
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Part of your problem is that you spread your code around all over the place which means that you need to scroll up down many pages to see where a variable is declared, initialised and then used.

There is a huge chunk of code in the middle of your program that I suspect could be replace by this:

                    $$dataref{$sid} //= &shared({});

                    $$dataref{$sid}{"ALL"} //= &shared({});
                    $$dataref{$sid}{"ALL"}{"MatchesStarted"}++;
                    $$dataref{$sid}{"ALL"}{"MatchesPeopleStarted"} += 
+$tn;

                    $$dataref{$sid}{$whichco} //= &shared({});
                    $$dataref{$sid}{$whichco}{"MatchesPeopleStarted"} 
++= $tn;
                    $$dataref{$sid}{$whichco}{"MatchesStarted"}++;


                    $$dataref{$eid} //= &shared({});

                    $$dataref{$eid}{"ALL"} //= &shared({});
                    $$dataref{$eid}{"ALL"}{"MatchesEnded"}++;
                    $$dataref{$eid}{"ALL"}{"MatchesPeopleEnded"} += $t
+n;

                    $$dataref{$eid}{$whichco} //= &shared({});
                    $$dataref{$eid}{$whichco}{"MatchesPeopleEnded"} +=
+ $tn;
                    $$dataref{$eid}{$whichco}{"MatchesEnded"}++;
[download]

Which might improve things a little, but I have no way to test that.