it really depends on what you're working through.
i do this on occasion while experimenting and thinking through an architectural design. what matters is whether the end result is representative of the time spent on iteration and writing thrown-away prototypes. i will often not start writing code until a reasonable path is formed in my head, and then i may write a prototype that doesnt work out and have to loop back and rethink various aspects. it may take a week with nothing but vague updates in daily standups, but then something awesome to show that has gone through a bunch of private "pre-alphas".
> For more senior engineers, it can happen because they like to work on their own and may be overconfident in finding solutions.
this really only applies if you:
A) dont have a history of delivering quality solutions to non-trivial problems
B) refuse to ask for help/feedback when you actually need it
typically, the rest of the team is working on other things. there would be little value in me pushing various crappy prototypes just for the sake of providing updates that only serve to distract people with information that will be out of date in 24hrs. "too many cooks in the kitchen" is a real thing, too.