Theme updates in Brave browser not applied

[joheriks]

To reproduce:

• Run skeleton-starter-flow and open in Brave (https://brave.com)
• Modify frontend/themes/my-theme/styles.css
• When page reloads in browser, notice that changes are not reflected (see attached video).

Note: this is a browser-specific issue, the same works in FF and Chrome. Note: hard refresh (Cmd+R) doesn't help. Opening the page in a new private window shows the updated theme, but the first reload in that window reverts back to rendering with the previous css.

Versions:

• Vaadin 20.0.0.beta1
• Brave Version 1.24.82 Chromium: 90.0.4430.93 (Official Build) (x86_64)
• MacOS Catalina 10.15.7

https://user-images.githubusercontent.com/2838896/117770593-c737bc80-b23d-11eb-9fc6-46014e6138b0.mov