"Aggregate Attribute with 0 matching attributes asks for a bug report"

The following minimalistic process, when run, throws an error box with a "Send Bug Report" button.
I don't have bugtracker login credentials, so here it is:

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<process version="5.2.008">
  <context>
    <input/>
    <output/>
    <macros/>
  </context>
  <operator activated="true" class="process" compatibility="5.2.008" expanded="true" name="Process">
    <process expanded="true" height="641" width="1013">
      <operator activated="true" class="generate_data_user_specification" compatibility="5.2.008" expanded="true" height="60" name="empty" width="90" x="112" y="75">
        <list key="attribute_values"/>
        <list key="set_additional_roles"/>
      </operator>
      <operator activated="true" class="generate_aggregation" compatibility="5.2.008" expanded="true" height="76" name="max_f_" width="90" x="313" y="75">
        <parameter key="attribute_name" value="max_f_"/>
        <parameter key="attribute_filter_type" value="regular_expression"/>
        <parameter key="regular_expression" value="f_.*"/>
        <parameter key="aggregation_function" value="maximum"/>
      </operator>
      <connect from_op="empty" from_port="output" to_op="max_f_" to_port="example set input"/>
      <connect from_op="max_f_" from_port="example set output" to_port="result 1"/>
      <portSpacing port="source_input 1" spacing="0"/>
      <portSpacing port="sink_result 1" spacing="0"/>
      <portSpacing port="sink_result 2" spacing="0"/>
    </process>
  </operator>
</process>