Fix for the new GV iOS app "high contrast UI'' bug
I've seen a couple of reports of folks having this problem. It is usually described with some curse words about the new UI. We thought at first that people didn't like the new "gradient" icons, but this is unrelated.
If your iOS Google Voice app is displaying texts in a chat as black and white, with black outlines, instead of the usual color-shaded bubbles, this is a bug. To fix it, see my answer in this post:
https://support.google.com/s/community/forum/589387/thread/439673305/message/440197533
I assume this will eventually get properly fixed by Google, but this is an interim solution.