i recently had a "first time" problem after almost 60 years of tying. Using one of my ceramic bobbins I broke my thread while tying, an occurance which does happen, but not often. As I wasn't doing any thing unusual it did seem a bit strange and I dismissed it as a weak point in the thread. However it became a bit stranger when I was unable to rethread my bobbin. As I was using unwaxed thread I knew that wax build up was not the problem.
As I mentally retraced my tying steps the culpert came to light. I had used a very fluid/ thin super glue to secure some slick hair and had let a larger than needed drop escape from the bottle. It had run off the fly, down the thread and into the bobbin tube. It took a bit of work to clean the tube but all is back to normal.
Who says there is nothing new in fly tying!