I recently wiped my phone and reinstalled the same custom, rooted, stock ROM.
Since then, when I rotate the phone, Chrome rotates the display (as expected) but then refreshes the page. The loading bar goes across, a YouTube video will stop playing, and depending on the page the scroll position is lost.
Before, the display would simply rotate in place without issue.
I have never seen this behavior before and I cannot find any relevant setting to change it, including in chrome://flags.
What is causing Chrome to refresh when I change the screen orientation?