Originally Posted by
Tartan
Been there, done that, bought the shirt. I know just what you are talking about and if you find the solution let me know. It only happens to me occasionally also but super frustrating when it happens. I clip the thread and re-thread the needle. I think it is when the thread from the needle actually sews through the thread.
I would rethread the upper thread, check the bobbin area to see whether there are any dust bunnies and rethread the lower thread.