[GAP Forum] An error message in cohomology calculations

[Anvita]

Dear Forum,

I have two seemingly resembling programs one of which
works while the other one does not. In both programs
I check if a certain matrix group splits over its central subgroup
of order two using OneCocycles. What is the reason
of the error message in the second case?

Thank you,
Anvita


Program 1
=================================
m1:=[
[2,0,0,1],
[0,2,1,0],
[0,0,2,0],
[1,0,0,1]]*Z(3)^0;;

m2:=[
[0,2,0,0],
[1,0,0,0],
[0,0,0,1],
[0,0,2,0]]*Z(3)^0;;

M:=Group(m1,m2);
C:=Group(-One(M));
IsSubgroup(M,C);
# true
OneCocycles(M,C).isSplitExtension;
# false
==================================

Program 2
==================================
m1:=[
[0,0,0,1],
[0,1,1,0],
[0,1,2,2],
[2,2,2,0]]*Z(3)^0;;

m2:=[
[0,0,0,2],
[0,2,0,0],
[0,2,2,1],
[1,1,0,2]]*Z(3)^0;;

M:=Group(m1,m2);
C:=Group(-One(M));
IsSubgroup(M,C);
# true
OneCocycles(M,C).isSplitExtension;

Error, no method found! For debugging hints type ?Recovery from NoMethodFound
Error, no 1st choice method found for `MovedPoints' on 1 arguments called from
MovedPoints( ocr.group ) called from
OCAddGeneratorsGeneral( ocr ); called from
OCAddGenerators( ocr, ocr.group ); called from
OCOneCoboundaries( ocr ) called from
OCOneCocycles( ocr, false ); called from
...
Entering break read-eval-print loop ...
you can 'quit;' to quit to outer loop, or
you can 'return;' to continue
==================================