@russian-dima ToUpdate has three elements .record, .field and .value
I think the trouble has something to do with chaining promises, and then passing a promise back to the calling code properly. From my limited understanding I thought that promises were supposed to be chained automatically, but the .then code does not seem to be behaving as if they are. That was the reason for switching to the await approach, which did seem to be an improvement (for a while).