I had massive unlogical problems with the trigger logs. for some triggers they were, for some they were not.
I read also this thread (for those who are searching a solution), but no solution for me: newbielink:http://community.welldonesoft.com/troubleshooting-8/no-trigger-logs/ [nonactive]
a possibly solution could be that you have in the name of one or more triggers a "%". I can replicate this bug. cancel the "%" and trigger logs work perfectly.