Half my fields showing question marks

[Ziphius]

I do studies with manta rays. I have two tables, SURVEYS and MANTAS. Each survey can have multiple mantas (MantaIDs). For each survey, the CountMantaIDs field shows the count of mantas for that survey. I have a second field to show the cumulative IDs for all prior surveys plus the current survey. This calculation field is called RunningCountMantaIDs with the result being number and looks like this:

If(Get(RecordNumber) > 1;GetNthRecord(RunningCountMantaIDs; Get(RecordNumber) - 1); "") + CountMantaIDs

The goal here is to get the cumulative total of all MantaIDs from that survey and all those prior.

For 177 of my 375 records my calculation is working fine, but after record 177 I'm only getting question marks. The field is plenty large to display the entire number and all fields are formatted to show a number result. For the first few fields after 177, when I click in the field, the proper value replaces the question mark but returns to a question mark when I click out of that field. This only works for a few records following record 177, then it just remains a question mark whether or not I click in the field.

Any ideas why only a portion of the table is working?

[Ziphius]

So it seems that Filemaker has a 10K limit on all recursions and may have been timing out part way through. Also, my use of the GetNthRecord to count running total was overkill, just needed to create a summary field that has the running total checkbox checked.

Another method was to create a self-join SURVEYS table with the instance called SURVEYSBEFORECURRENT via the relationship SURVEYS:SurveyNo is > or = SURVEYSBEFORECURRENT:SurveyNo. Then create a summary field and show it through the SURVEYSBEFORECURRENT table.