I experience similar things. This is just my own theory, but I think certain words/ phrases have a long history of fear behind them, and context is key. Maybe in the past you’ve tended to block when someone asks you your job title, and your mind remembers that and braces for the block preemptively. Like falling into a well-worn groove. But when you use that phrase in a different context your brain doesn’t have the same association. You’re able to say it more spontaneously. Just a thought. It’s frustrating for sure. Glad you’re in a good place overall with your stutter.