Google Chrome background processes icon not displaying properly in MATE
 

I just installed Ubuntu MATE 19.04 on my laptop yesterday and happened to noticed that Google Chrome's background processes icon doesn't display properly (appears as a GTK 'empty app' icon) which is clickable and still works properly. If Chrome's app icon comes up in the start menu, why won't the background processes icon show up properly in the panel?

Try different icon themes.

That said, please be aware that Chrome is closed sourced software, and therefore can never get full Linux support.
Not because of ethics but because distro developers simply cannot know what icon Chrome is requesting, for example.