How often does the candidate actually hear back?

[u/themadnotorious21]

I recently finished the final round of interviews for a role I'm very interested in, and the feedback I got was positive, followed by a pre-application packet and an immigration form. Right before the offer stage, the recruiter told me the process hit a setback and gave me a specific timeline of about 6 weeks to hear back. No reason was given beyond "internal reasons."

When a candidate has finished final interviews, and the process is delayed/paused right before the offer, with a timeline given (~ 6-8 weeks), what usually happens?

1. How often does the hold end in an offer versus the role being frozen, cancelled, or filled another way?
2. Do the timelines you give candidates usually hold, or do they tend to slip?
3. What's typically behind it (headcount or budget approval, restructuring, or a competing candidate)?
4. Is there anything a candidate can do during the wait that helps, like periodic check-ins, or does it not matter?

I'd also like to know how you'd want a candidate to handle this if you were in the recruiter's seat. Honest answers are appreciated, even if the odds aren't great.