TLX00010 validation is throwing an exception, but can't figure out why

We have a case where we are reporting leave (vacation), but it is throwing an exception on the last date reported.

Employee is paid via the work schedule (M-F, 7.5 hours/day). The work schedule was applied on the timesheet and replaced with our leave TRC (VCH). This was successful for all days between August 12 and 29th, but August 30th was where the exception occurred. We allow a large negative balance (999 hrs), and balance goes into a negative even before August 30th hits (less than 50 hrs). Leave Plan set up, employee enrollment, empl rcd, ben rcd....all seem fine.

Does anyone have any idea on what might be causing this?