My buttons all have a highlight around them after I click them. This is in Chrome.
my understanding is that the focus is first applied following the onMouseDown event, so calling e.preventDefault() in onMouseDown may be a clean solution depending on your needs. This is certainly an accessibility friendly solution, but obviously it adjusts the behaviour of mouse clicks which may not be compatible with your web project.
I am currently using this solution (within a react-bootstrap project) and I do not receive a focus flicker or retained focus of buttons after a click, but I am still able to tab my focus and visually visualize the focus of the same buttons.