I think the result is not jarring but a feeling of familiarity.
If you spend all your time on Android and the Web, an for some reason occasionally use a Google app on an iPhone it may feel familiar to you.
But if you have an iPhone chances are you spend a lot of time using other iOS apps (including the system ones) and are used to that design language.
It's nice that it's consistent with other Google products, the problem is that's the wrong thing to do on iOS because it feels so out of place. You can still use your colors and many of your other schemes, but basic platform conventions like share buttons and menu locations should be respected.
most iOS users I know don't use share buttons anyway. I always get a stupid screen shoot of a web page with a url
I imagine part of the problem is they added it 5+ years into the platform when most people already had a way of doing things, even if it was sub-par, and they haven't been able to convince people to use it much.