>>>Deleted record was the solution.
>>>Late coworker had added a place to delete records I've never thought off.
>>>
>>>Customer seems to use this on regular base, but normaly the garbage collection catches the problem.
>>>
>>>(>ლ)
>>
>>An index on !deleted() may help
>>

>>index ..... for !deleted() 
>>

>
>Changing tableupdate(0, to tableupdate(.T., solved it an instance without touching the index. It was very simple. :) I will keep the FOR clause of INDEX in mind, anyway.

INDEX... for disables Rushmore optimization