Past ?5+ days after I get on here, and -then touch my phone screen to move the image- it starts flashing

briefly; for a bit...2 to ?5 times then stops.
Almost every time I go to a new "page" it does it again.

Past few days, I've had a few "sign ins" (not so unusual). I've restarted my phone; that hasn't helped.
Oh, and this is not happening on any other site, I've gone to, apps used, etc .

So ...Any suggestions, info etc
TIA!