experimental::AudioEngine::remove Crash on IOS

Facing random crashes on LIVE game with stacktrace cocos2d::experimental::AudioEngine::remove(int) + 2586436
Here is the detailed stacktrace below. also attaching screenshot of fabric

#0. Crashed: com.apple.main-thread
0  SlotGame-mobile                0x100ab5ba4 std::__1::unordered_map<std::__1::basic_string<char,             std::__1::char_traits<char>, std::__1::allocator<char> >, std::__1::list<int, std::__1::allocator<int> >, std::__1::hash<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > >, std::__1::equal_to<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > >, std::__1::allocator<std::__1::pair<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const, std::__1::list<int, std::__1::allocator<int> > > > >::operator[](std::__1::basic_string<char, std::__1::char_traits<char>,     std::__1::allocator<char> > const&) + 2585268
1  SlotGame-mobile                0x100ab6034 cocos2d::experimental::AudioEngine::remove(int) + 2586436
2  SlotGame-mobile                0x1008b790c cocos2d::experimental::AudioEngineImpl::update(float) + 495644
3  SlotGame-mobile                0x1008b9b80 cocos2d::Timer::update(float) + 504464
4  SlotGame-mobile                0x1008bc6c0 cocos2d::Scheduler::update(float) + 515536
5  SlotGame-mobile                0x1008f58ec cocos2d::Director::drawScene() + 749564
6  SlotGame-mobile                0x1008f6ef4 cocos2d::DisplayLinkDirector::mainLoop() + 755204
7  QuartzCore                     0x18a8f7f24 CA::Display::DisplayLinkItem::dispatch(unsigned long long) + 44
8  QuartzCore                     0x18a8f7dd0 CA::Display::DisplayLink::dispatch_items(unsigned long long, unsigned long long, unsigned long long) + 444
9  IOKit                          0x187916094 IODispatchCalloutFromCFMessage + 372
10 CoreFoundation                 0x18763ee50 __CFMachPortPerform + 180
11 CoreFoundation                 0x187657218 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE1_PERFORM_FUNCTION__ + 56
12 CoreFoundation                 0x1876569cc __CFRunLoopDoSource1 + 436
13 CoreFoundation                 0x1876544b0 __CFRunLoopRun + 1840
14 CoreFoundation                 0x1875822b8 CFRunLoopRunSpecific + 444
15 GraphicsServices               0x189036198 GSEventRunModal + 180
16 UIKit                          0x18d5c27fc -[UIApplication _run] + 684
17 UIKit                          0x18d5bd534 UIApplicationMain + 208
18 SlotGame-mobile                0x1000f4304 main (main.m:6)
19 libdispatch.dylib              0x1865655b8 (Missing)

I also experienced a same issue.

But, I yet couldn’t find a cause