Burndown Chart Does Not Calculate Edited Worklogs Correctly

Steps to Reproduce:

Create an issue with an original estimate of 8 hours. The log work for 8 hours, automatically adjusting remaining estimate.

Current status should be 8h Original Estimate (OE), 8 Hours Time Spent (TS), 0 Hours Remaining Estimate (RE)

Now log work again, this time working 1 hour and adjusting the RE to 2h.

Then edit that work log, so that the 1 hour worked is now 2.5, and the RE is 0.5h instead of 2h.

Now create a new sprint and add just this issue to it.

Expected Behaviour:

As of the last update before being added into the sprint, the issue had 30minutes remaining. I would expect the RE to be 30 minutes in the Burndown Chart

Actual Behaviour:

It will end up being reporting as having negative 1.5 hours remaining.

Other info:

Michael R says it's possibly because it's parsing the edited entry and not the other change.