Joshua regrets offering fury sparring session

It sounds like Joshua is having some second thoughts about offering Fury a sparring session. It's understandable to have doubts or regrets, especially when it comes to a high-stakes situation like a boxing match.

Can you tell me more about what's going on? What made Joshua regret his decision to offer Fury a sparring session? Was it something specific that happened during the session, or is it more of a general feeling he has?