Folder scan strange behavior

Can someone explain why did this happen.
I started a folder scan and selected almost everything on my drive D
At one point I saw the scan process were at 13% and the circle was with red and blue color inside but shortly after that I saw that the the scanning process started again from the beginning,the blue circle inside is now red and I notest that it’s scanning the folders I told him not to scan.

I using the latest Avast Free
And also for some reason,avast suggest Smart Scan almost every time I start the pc