I've noticed them too.

Go to Google Search, Gmail, any Google app.

On the right top "grid" icon, you can see most of the rebranded icons.

If you want my opinions, they are less readable, and they adopt different aspect ratio (some are rectangle, some are vertical, no homogeneous aspect) which increase the messy feeling.

I largely preferred they adopted a common basis (a rounded rectangle or circle would have done the job). Some icons have stayed the same, which is also confusing. Either you change anything or nothing in my opinion.