ios – iphonexs max crashes, and this always happened when the application came back from the background in the foreground

[CAGradientLayer _clearContents]: Unrecognized selector sent to 0x2815c31a0 instance

CoreFoundation ___exceptionPreprocess + 232

1 libobjc.A.dylib objc_exception_throw + 60

2 CoreFoundation -[NSOrderedSet initWithSet:copyItems:]

3 Foundations ____forward___ + 1412

4 CoreFoundation _CF_forwarding_prep_0 + 96

5 UIKitCore -[UILabel _startMarquee] + 3332

6 libdispatch.dylib __dispatch_call_block_and_release + 32

7 libdispatch.dylib __dispatch_client_callout + 20

8 libdispatch.dylib _dispatch_main_queue_callback_4CF + 1012

9 CoreFoundation _CFRUNLOOP_IS_SERVICING_THE_MAIN_DISPATCH_QUEUE + 16

10 CoreFoundation ___CFRunLoopRun + 1888

11 CoreFoundation CFRunLoopRunSpecific + 452

12 GraphicsServices GSEventRunModal + 108

13 UIKitCore UIApplicationMain + 216

14 Èáëõõø main (main.m: 14)

15 libdyld.dylib _start + 4

and this only happened iphonexs, and this always happened when the application came back from the background in the foreground, could you help me, thanks