You must be giving it a hash instead of an array ... don't know how you managed to write that :)

[% MACRO blocker BLOCK %]
[%     FOREACH element IN array.sort('name') %]
[%         element.name %]
[%-    END -%]
[%- END -%]
[%-
SET array = [
      { name => 'foo', value => 1 },
      { name => 'bar', value => 2 },
      { name => 'baz', value => 3 }
    ];
    blocker;
%]
[%-
    SET array = [ { name => 'bar', value => 2 }, ];
    blocker;
%]
[%-
## A HASH IS NOT AN ARRAY OF HASHES
    SET array = { name => 'bar', value => 2 };
    blocker;
%]
[download]

yadayadayada

* bar
* baz
* foo

* bar

*
*
[download]