Crashing under release builds w/ iOS SDK 18.4

Hello! 

I'm getting a crash when building against 18.4 - only for release builds, debug builds work ok. This is the crash output:

```
*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[__NSMallocBlock__ eventType]: unrecognized selector sent to instance 0x300d7e4f0'
```