I have just noticed that adding an action to the Hint element causes the Hint text to be indented - the amount of indent corresponds to the icon+button text used.
This is somewhat annoying, especially for mobile apps. If you have a hint with a lot of text the entire text gets squashed despite the fact the action button is in the header part of the Hint and doesn’t impact the text below.
I have given up using actions in hints because of this.