Collector creates non-contiguous issues

We set up a collector to create bugs from an email account at our company. I noticed that the bug number does not increment contiguously as would be expected (BUG-3, BUG-4, BUG-5, etc.) Instead it seems to vary wildly. Real issues: TEMP-1428, TEMP-1431, TEMP-2672, TEMP-3019, TEMP-4987, TEMP-5392, TEMP-7474, etc...

The collector was doing this in the main project so I pointed it to the temporary project to quit burning through insane amounts of issue numbers. No one is manually creating issues in the project so there's no other way to account for this behavior. I've tried to browse to some of the issues in between (TEMP-7300) but it does not exist.

The run up from TEMP-1428 to TEMP 7592 was only 5 days (March 29 to April 2).

I'm not filing this as a support request because I can't see any possible reason this would ever be desired behavior regardless of configuration.