This issue has plagued us and it is really difficult to investigate. If a tester is to enter a #.# value into the elasped time. i.e. 1.5h, 0.5d, it submits the value after the decimal and as a whole number.
This significantly bloats certain test sessions as a 0.5 days becomes a week and 0.5h becomes 5hrs. It too is a common misconception because Jira allows values of this type to be entered so habits become difficult to break.
With hundreds of results entered each day, it can quickly bloat our numbers and it too is difficult to know if 3.5 or 4.5 hours was meant to be entered where 5h becomes the result.