What avast version are you using.

I have just run a full system scan to do some testing. There were three detections and that was displayed in the Notifications - Issues and I dealt with them there - I then went to the Scan History and highlighted the scan I had just done.

If you then click on Detailed report it brings up another screen, this shows the detection/s and confusingly offers Actions. Since this is essentially a historic record and not the live scan result the actions can’t be applied.

See attached image, is this what you were looking at ?