Quite an important detail … the gtk3 theme is handled by lxappearance-gtk3 but still should not influence negatively the way Chrome or Chromium display … see
Will investigate more once i got some more time, or maybe someone else has the answer about it, but right now is not very obvious for me why is not working for you.
I’m using KDE and have noticed the same issue for a while now. I’ve played with the themes and settings just as mentioned here. The only thing I’ve found that ‘fixes’ it is to remove the google-chrome folder from ~/.config, which restores the correct colors. But if I close Chrome and open it again, even without signing into anything, it goes back to following Manjaro system colors.
Another thing that I have noticed that might be linked to the whole thing is that my mouse cursor has changed? I get the default manjaro mouse cursor while I move my cursor within google-chrome, but when I move it outside, I get DMZ-Black, which I have set up in my system configuration. Just for chrome it seems to be ignored.