Time out on the web application

Like other MacOS users, I'm waiting for the native app. So far I've been accessing To-Do from to-do.office.com. I discovered that if I use Safari, To-Do would time out every 1 hour or so, forcing me to login again. This is so annoying. However, if I use Chrome, the time out is much longer (I'm guessing somewhere 12-18 hours). Not sure about other browsers.

Does anybody else experience this? Why make the experience different between browsers?