I bought a new card rtx 2070 super, and this issue gone. now i don't see those lights. and also i updated my windows before new card. maybe that solved my problem i don't know.
by the way its not only opening scene, those flashes everywhere and so bothering. even you walk, you can see those colorful lights at your foot. so annoying.
@pale_rider_tv okay, coz it doesn't work in hdd when you have ssd.
@pale_rider_tv is it in your hdd or ssd?
have same problem, gtx 960 gaming 4g.
if you have ssd and game location is in hdd then it won't work. i had same trouble but i fixed it. transfer to ssd, select locate game in ubisoft connect, locate game in your ssd and play.