I get a long wait, high CPU usage and an eventual "white screen of death" after generating aliases for taxonomy terms. This did not happen until Taxonomy Manager module caused some problems with a few terms that were assigned to themselves as children numerous times. Taxonomy.module UI was listing many terms as children of themselves recursively. I was able to make the term list in taxonomy.module's UI appear correctly by removing the parent assignments for those terms, but pathauto is still not completing the generation. It generates 12 terms before it stops. I tried setting the limit of aliases generated per execution to 10, but that did not solve the problem. Any idea how I might clean this up?