I am experiencing the same issue as well in Chrome. When I navigate between tabs, I get a "Are you still there? I'm back" pop up I have to tap in order to view the page again.
I have the desktop app open and use that the most but then use Chrome to have three other channels open to be able to monitor chat, grab files, update spreadsheets, etc, without losing my spot in the desktop app (it's like having multiple folders open to
gather needed incoming files/details). I don't see a way to have multiple channels open at once, so opening in the web is the solution.
But that pop up happening in Chrome (preferred browser) is driving me crazy.