Crash when writing JSON

[jkmassel]

Thread 0 Crashed:
0   CoreFoundation                  0x316f0c9d8         __exceptionPreprocess
1   libobjc.A.dylib                 0x33f72cb50         objc_exception_throw
2   Foundation                      0x3194edcf8         _writeJSONValue
3   Foundation                      0x3194f04dc         ___writeJSONObject_block_invoke
4   CoreFoundation                  0x316e77cc4         __NSDICTIONARY_IS_CALLING_OUT_TO_A_BLOCK__
5   CoreFoundation                  0x316df4600         -[__NSDictionaryM enumerateKeysAndObjectsWithOptions:usingBlock:]
6   Foundation                      0x3194efa40         _writeJSONObject
7   Foundation                      0x3194f07d0         ___writeJSONArray_block_invoke
8   CoreFoundation                  0x316e901cc         __NSARRAY_IS_CALLING_OUT_TO_A_BLOCK__
9   CoreFoundation                  0x316df4368         -[__NSArrayM enumerateObjectsWithOptions:usingBlock:]
10  Foundation                      0x3194efee4         _writeJSONArray
11  Foundation                      0x3194f04dc         ___writeJSONObject_block_invoke
12  CoreFoundation                  0x316e77cc4         __NSDICTIONARY_IS_CALLING_OUT_TO_A_BLOCK__
13  CoreFoundation                  0x316df5814         -[__NSDictionaryI enumerateKeysAndObjectsWithOptions:usingBlock:]
14  Foundation                      0x3194efa40         _writeJSONObject
15  Foundation                      0x3194edbcc         -[_NSJSONWriter dataWithRootObject:options:]
16  Foundation                      0x3193ab980         +[NSJSONSerialization dataWithJSONObject:options:error:]
17  WordPress                       0x20376e620         -[TracksServiceRemote sendBatchOfEvents:withSharedProperties:completionHandler:] (TracksServiceRemote.m:43)
18  WordPress                       0x20376c428         -[TracksService sendQueuedEvents] (TracksService.m:168)

https://sentry.io/share/issue/270bf6bc44ea42dd952b4c3ac5e6b235/