So you work in some scrum framework with tasks and sprints? I wonder how feasible that is in frameworks like that
At some point I stopped bothering. I can't worry about the company more than the company worries about itself. I think that's fair.
Should it be that way? No, but it sometimes is.
(Just a disclaimer, I do it too)
I don't think it's ever been secret in companies that I work for that devs don't spend 100% of their time on assigned tasks. There are always extra things like customer support, ops, urgent requests, unexpected refactoring that come up and have to be dealt with. Project managers I've worked with have mostly cared about the estimate being as accurate as possible taking into account these overheads.