I bought 2 Ronin batteries (4350mAh) from the Dji store. I tested both of them on 3 Ronins now. They light when I started them, like the original battery, but then they start flashing, and nothing happens. Anyone has had this issue before?

Hello.
The new Ronin battery (4350mAh) is only compatible with the latest firmware, so, have you upgraded your Ronin to the latest firmware? Or what's the firmware version of your Ronin?
Also, please make sure you've balanced the camera before powering on the Ronin.

Wait for your reply.
Thanks.