I personally find that there is a huge difference between talking to a coworker about their hobbies, or their last pull request. Talking about the job at hand

I personally find that there is a huge difference between talking to a coworker about their hobbies, or their last pull request. Talking about the job at hand is never an issue. But it's also best to leave it at that to keep the work environment constructive, and not e.g. split a team among party lines. (In my experience, we are now also talking about a purely hypothetical scenario. At the workplace I spent most of my career, team leads were generally hired externally, or promoted based on nepotism and "company loyalty" [read: years spent working at the company] rather than skill)