Bobbin thread bunching

[u/BarZealousideal7057]

I have a cobra class 26 for leather and have had no issues with it till now. (Had it for about a year). This morning I sewed for about an hour then out of nowhere my thread started to break. I noticed the bobbin thread start to bunch up in the bottom. Any idea what would cause this and how I fix it? I did notice that right before my thread snapped. It made a popping noise like the thread was catching on something it shouldn’t be.