Maybe Mdevices only has one record in it? You only show a single push of an array reference into it. You can use Data::Dumper to help visualize your data structures. 
use Data::Dumper;
print Dumper(\@Cdevices);
print Dumper(\@Mdevices);

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This may also be of use: References quick reference

In reply to Re: Multidimensional array by toolic
in thread Multidimensional array by igor1212

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