Had this happen on 9spd SRAM chain/SRAM Quick Link about 13 years ago. Once they wear enough, the only thing keeping the links together is tension. If I took my chains off to clean them and connected the links, the Quick Links oft would just fall apart and on the floor because they weren't under tension. Sometimes they would even fall apart if I removed the back wheel and chain was slack. This was before the Quick Links actually locked, or SRAM said they were one time use.
Your 45NRTH chain was made by Yaban (YBN). I'm not sure who made/what links 45NRTH had with them - they are discontinued now.
The new KMC Missing Links are good quality, and be reused without issue. If using Shimano, I'd just stick with Shimano master pins.
Last edited by Jamminatrix; 08-02-15 at 06:10 PM.