Updating from 17.4.2292beta UI.
Edit1: Just rebooted and the first thing that I did was run a Quick Scan and boy was it quick, it was finished in the time it took to open the scan interface and that was under a second. Just the big Green tick and Great No issues found. So much so that I had to check the logs to see if it did scan, no record in the Quick scan.txt log for the quick scan, generate report file is enabled.
No record of the Quick scan in the UI Scan history, so something wrong here.
EDIT2: Started a Full Scan and it hung on 0% for absolutely ages and has now started to display the progress percentage. I notice the Pause button is still AWOL (Absent WithOut Leave). This would be a real pain if you happened to need to pause to do some work, all you have is to cancel and when ready start the whole bloody scan AGAIN. The Full Scan has completed with success, no issue with the scan cancelled issue, but then again I didn't suffer with it in the last beta or previous regular release.
Record of the full virus scan.txt file and also in the UI Scan history, this was recorded correctly.
Personally I don't bother with on-demand scans other than beta testing and in relation to forum topics. But there are many users that do use the on-demand scan function.