Android: Intent extras not being received when launching an already-open UnityPlayerNativeActivity

I'm trying to make two Unity Android apps communicate with each other using Intents. I made a custom UnityPlayerNativeActivity and used it on both apps. When app A sends an intent to app B (which has not yet been launched), the Intent extras are received perfectly. But when app A does the same to an already-launched app B, all my extras are not loaded and instead i got the different extra named "profile" with the value of 0. How can I make this work?