I have this very weird problem, where some of my purchased items entries have the same exact URL Title as others.
The site is set up where a event participant gets sponsors to participant in a fundraising event. So the sponsor (customer) is purchasing a sponsorship that is credited to the participant. And the “purchased item” is on the fly, set up as “Participant sponsorship of firstname lastname in event name 2012” and the URL title, it seems if there are more than one sponsorships, comes out as “sponsorship-of-participant-firstname-lastname-in-event-2012das”
What it HAD been doing, was adding a number of the end of the 2012 - as expected with EE. Some other entries are that way. 20121, 20122, 20123, and so forth. In one case there was a 2012dash4 and I fixed that manually (removing the word dash) and all was fine. But clearly there is something weird happening.