HWM_CTXARY_RECORD_POSITIONS shows different value after changed expenditure type in fast formula

Hi All,

I tried to create a fast formula to validate time entry information:

When the date is a public holiday, user can only enter specific hours for specific expenditure type.

I used HWM_CTXARY_RECORD_POSITIONS to get the hours entered everyday, but meet following situation in UI:

Not change expenditure type, Click save:

HWM_CTXARY_RECORD_POSITIONS.count = 24

HWM_CTXARY_RECORD_POSITIONS[nidx] include DETAIL

After change expenditure type, Click save:

HWM_CTXARY_RECORD_POSITIONS.count = 15

HWM_CTXARY_RECORD_POSITIONS[nidx] NOT include DETAIL

I need the DETAIL data in my fast formula.

May I know why this situation occurs while I just change the expenditure type?