Yes.
If I was in Twitter where it was happening, my phone would open thread, or reply window.
Things that act like adware or malware.
I ended up doing factory reset (not restore) that seemed to solve it. And I am careful with apps and sites or opening links.
Adguard and Malwarebytes we're already installed.
Normally on Samsung it's easy to wipe cache partition but I have trouble getting into boot menu that can. (Wish "clear cache partition" was listed where other resets are for network etc)
I also thought it might be pressure from case and to use bare. No help.
Reboot as you found is only temporary fix.