I found FAQ below to be helpful—any other helpful links? https://kite.trade/forum/discussion/8019/faqs-on-pykiteconnect-specific-to-python-client#orders
I just placed a MARKET order from the kite publisher and COMPLETE status is received absolutely fine on the postback URL. You need to inspect your local postback setup. Go through postback FAQs here.
We have created the SL order using the kite api. When order status changes to completed/cancelled, the updated status does not return to the postback url.