Repeated captures do not work. Only the last repetition actually captures anything. Contrast:

my @captures = 'abcde' =~ m[(.){3}];
print "@captures";;
c
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with

my @captures = 'abcde' =~ m[(.)(.)(.)];;
print "@captures";;
a b c
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and

'abcde' =~ m[(.){3}] and print "$1,$2,$3";;
Use of uninitialized value in concatenation (.) or string at ...
Use of uninitialized value in concatenation (.) or string at ...
c,,

'abcde' =~ m[(.)(.)(.)] and print "$1,$2,$3";;
a,b,c
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all these regexes are untested.

You might consider revising that policy.