With Windows 10 OS, whenever you made a medium or high fast stroke in Clip Studio Paint (CSP), If you see the "hooks" at the beginning of the line, similar as below:
Please open the sub tool detail of the pen tool and check [Adjust by speed] in the correction item.
To do that, follow the detailed instructions below.
Open Clip Studio Paint, then click on [Window], scroll down to [Sub Tool Detail] and select it.
 Select [Correction]. This will open the settngs for correction pen touch.
 Check [Adjust by speed], close Sub Tool Detail dialog box, and test.
The "hooks"should have disappeared.
If you are using PC for Windows 7 OS, I suggest that you upgrade the PC OS to Windows 10 first, then refer to this instructions to set up.