Set Field and then Exit Record?

I came across something new recently. I had a script that would only work when I inserted a Pause/Resume script specified as indefinately for the duration after a script step that set a field. I couldn't get it to work without the Pause/Resume step, even if I set it to pause for one second instead of indefinately.

I spoke with another developer about it, and he suggested that I use Exit Record/Request, which worked. He said that he had come across such behavior on occasion with FileMaker, and to make sure it didn't happen, practiced the habit of putting an Exit Record/Request step after every Set Field request.

That seems to be overkill to me, but I'm wondering if this behavior is predictable. In this particular case, I was setting a date field to a calculated result (based on the date in a global field and adding a number of days to it based on a number in the middle of a text field). In fact, here's the code of the line where it happened:

Set Field [ Start_Date, gNew_Schedule_Start_Date + TextToNum( Left( gDifference_Array, Position( gDifference_Array, "^", 1, 1 ) - 1 ) ) ]

Can I predict when I need to use the Exit Record/Request step after Set Field steps by noting what kind of field I'm setting and what kind of data I'm setting it to? Did the fact that it was a date field have anything to do with it? The fact that it was a date field and that what I was setting it to was based on a global date field? See what I mean?

Also, has anyone else ever come across this?

Thanks,

Chuck