Recent projects on the Android is always random crashes (exit) silence, investigating the log an error:
11 (Fatal signal SIGSEGV) at 0 x00000004 (code=1), the thread (thread - 2769) 3604
To check the problem belongs to the Mono layer WWW multithreading (each thread a WWW) calls the same JNI methods lead to collapse.
Tried many kinds of methods: parallel loading quantity control, line up, the main Thread Thread. Sleep, all is invalid, in the case of a single line (not parallel) is still a random crash, and crash the loaded file is still a random number of 200 + collapse, sometimes sometimes 20 collapse.
Forced to eventually replace the Unity version to 5.6.3, problem solved.
Problem summary, belongs to the Unity of the underlying their Bug. Question no progress should be a change of direction in time, check this issue for a week. The direction of the right should be identified in a day or two.