When switching to a tab that has Github open, it can take upwards of 10 seconds before the page displays

Open a page in github (any page will do, repo code, PR, issue, whatever)
Open new tabs in the browser for other things, keep doing this for a few hours
Need to use github again, rather than open a new tab, click on the tab opened in step 1

Expected: the page content was as it was before, or the browser tombstoned the tab and its actively reloading

Actual: the page is blank and stays that way for 5-10 seconds before showing

I noticed this started to happen in the last few weeks/months. Its annoying at worst, is there something that can be done about it?

Github.com is the only site that does this, and it does this on both my work and home computers, so I’m not thinking its a browser or environmental issue.