My app shutdown without warning

Hi,

i used Unity version 5.3.1. I open my game scene and its work fine, but after i play in that scene (maybe about 30minutes or more) the app suddenly closed without any warning such "The app is shutting down". What i have done :

1. i used pool, so i reused the game object. I think there is no problem with garbage collector

2. i used many spine animation in that scene

3. i connected my device and see my profiler, it showed :

     - FPS about 15-60
     - draw call about 25
     - total memory usage : about 80MB and quite stable, no spike
     - audio : about 14MB
   
   

My device have 1Gb RAM. When the app shutting down, is this a memory leak?? but i don't see something wrong in profiler. What else can i do to fix the problem?

Please for your help, thank you.

Regards, Cindy