Hey there @Trung Le Dang, Emily here from Support Engineering at Intercom 
Would it be possible for you to update your React Native version to Release 8.3.0 which you can find here 
This will ensure this issue is not a bug that has been fixed in more previous versions.
If the version update does not fix the issue, would it be possible for you to open up a conversation with out support team for further analysis? As this behaviour does indeed appear as buggy.
Thank you!
Hi @Emilygav , thanks a lot for your reply, I’ve upgraded to version 8.3.0 but the issue still remains.
One thing I found out that, it seems like Intercom chat is combining previous message notification.
For ex: If I receive message notification with title “Hello” but I don’t swipe to delete that notification, and then I receive another message notification with title “Hi there” then 2 notifications are combined. Therefore, the more message notifications I get, the more it looks weird, I don’t know whether this behavior handled by system or internally by Intercom.
If I delete “Hello” notification, then when I receive “Hi there”, I will only see “Hi there” with out previous message “Hello”.
Hopefully my explanation makes sense to you. Please help me contact to Intercom Devs and let them know this behavior, I’ll really appreciate it. Also if you need any further information, please let me know, I’m willing to help do that.
Thank you so much.
@Trung Le Dang It’s Mat from the Support Engineering Team 
Please reach out to us via Messenger in your Workspace for us to investigate it further and in detail.