HPC-GAP Error: from TaskResult(): the families of the element or collection <elm> and Source(<map>) don't match, maybe <elm> is not contained in Source(<map>) or is not a homogeneous list or collection

[jaslamMiktex]

Update Oct 10, 2023 ----
I have been able to circumvent all the read-access errors by DISABLE_GUARDS(2);
NOTE: SetMaxTaskWorkers (4) or SetMaxTaskWorkers(16) does not make more 10% difference in the performance (running time).
PS: I am using a 8-core Ryzen 7 CPU.
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Hi All,
I have a perfectly working program in standard GAP 4.12.2.
The HPC version is giving a fundamental kind of error on TaskResult() which I cannot understand. I could not find any reference anywhere.

TaskError(task[j]) from TaskResult() >>>>>>>>>
"Error, the families of the element or collection and Source() don't match, maybe is not contained in Source() or is not a homogeneous list or collection"
I did not notice the "homogenous" condition to be the problem.

The programming context is somewhat similar to the "demo/matmult.g" in the demo directory of HPC-GAP.
BTW, in regular GAP 4.12.2 (hpcgap NOT enabled), this HPC code (with RunTask(), etc., calls) runs correctly, w/o any errors,
but of course, no multitasking is observed.

Will highly appreciate any explanation of this error.
testTaskGIT.txt

PS: in case somebody would be curious enough, I have attached the client code also.
Thank you so much
-Javaid