I've made some progress. I got it to work without that error by making sure I was either editing or creating a new inventoryassignment line as appropriate. if(i < count){ //edit existing inv detail (lot/serial preset on order) log.debug("setSubRecord",'edit line');…

I'm having this same issue when transforming a sales order to a item fulfillment. I did all the things the OP mentioned, stringifying both the subrecord and the inventory assignment lines. Everything looks good; all fields filled correctly. Is this really a bug in SuiteScript 2.0? Has a defect been created? Does this mean…