Brave not starting

Sometimes Brave will not start. I have in the past cleared the problem with a reboot of Windows 10.
Today it happened again. I started the Task Manager and there were 10 instances of Brave.
Killed them all and brave started as normal.
Windows 10 1903 OSB: 18362.657. Brave: Version 1.4.95 Chromium: 80.0.3987.122 (Official Build) (64-bit)

Its a bit inconvenient to keep rebooting.
Is Brave not cleaning up on exit or is it Windows?

Thank.