This isn't really a question, because I know there's no answer. But I felt obliged to tell you anyway.

In a suitelet (suiteScript 2.1) I have:

                ifLineSublist.setSublistValue({

                    id: 'itemctncnt',

                    line: lineIdx,

                    value: calcCartonCount(ifData.item_sublist[lineIdx].quantity, itemData)

                });

That code ran just fine at 5PM yesterday in our sandbox. Now it pukes with

"type": "internal error",

"code": "INVALID_FLD_VALUE",

"details": "You have entered an Invalid Field Value 339.0 for the following field: itemctncnt",

The fix is to change the value property to

                  value: calcCartonCount(ifData.item_sublist[lineIdx].quantity, itemData).toString()

Hint: It's an integer. The function being called uses parseInt() to make sure it returns an integer. It used to automatically cast an integer to a string properly, and now it doesn't. Expect lots of production code to break, at great expense to you and your customers. Congratulations!