If I manually add in some time for work completed, where the work goes past midnight, the system changes it to negative hours.
So for example, I added some time yesterday starting at 7pm and ending after midnight at 12:45am. Whether I use the up/down arrows to increase the time, or enter it manually, as soon as it goes over midnight it decides the duration should be a negative value - even though at the same time, using the arrows, it has understood that we've gone from PM to AM and made that change itself.