WatchKit extension crash: "Program ended with exit code: 0" - ios

Question

For people wanting to reply quickly without reading the post: I am not hitting any memory limits. Read the whole post for details.
My WatchKit extension cannot properly function without the user first being "onboarded" through the phone app. Onboarding is where the user must accept the permissions that we require, so it's very crucial.
On my WatchKit extension, I wanted to display a simple warning for users who had not finished onboarding within our phone app yet.
As such, I thought I'd get the status of onboarding from the phone in two ways:
When the user opens the app/the app is activated (I use the willActivate method to detect this)
When the app finishes onboarding it sends a message to the watch of its completion (if the extension is reachable, of course)
Both of these combined would ensure that the status of onboarding is always kept in sync with the watch.
I wrote the first possibility in, utilizing reply handlers to exchange the information. It worked just fine, without any troubles. The warning telling the user to complete disappears, the extension does not crash, and all is well.
I then wrote in the second possibility, of the extension being reachable when the user finishes onboarding (with the phone then directly sending the companion the new status of onboarding). My extension crashes when it receives this message, and I am stuck with this odd error.
Program ended with exit code: 0
My extension does not even get a chance to handle the new onboarding status, the extension just quits and the above error is given to me.
I am not hitting any sort of memory limit. I have read the technical Q&A which describes what a memory usage limit error looks like, and I don't receive any sort of output like that whatsoever. As well, before the extension should receive the message, this is what my memory consumption looks like.
I have monitored the memory consumption of the extension right after finishing onboarding, and I see not a single spike indicating that I've gone over any kind of threshold.
I have tried going line by line over the code which manages the onboarding error, and I cannot find a single reason that it would crash with this error. Especially since the reply handler method of fetching the onboarding status works so reliably.
Here is the code of how I'm sending the message to the watch.
- (void)sendOnboardingStatusToWatch {
if(self.connected){
[self.session sendMessage:#{
LMAppleWatchCommunicationKey: LMAppleWatchCommunicationKeyOnboardingComplete,
LMAppleWatchCommunicationKeyOnboardingComplete: #(LMMusicPlayer.onboardingComplete)
}
replyHandler:nil
errorHandler:^(NSError * _Nonnull error) {
NSLog(#"Error sending onboarding status: %#", error);
}];
}
}
(All LMAppleWatchCommunicationKeys are simply #define'd keys with exactly their key as the string value. ie. #define LMAppleWatchCommunicationKey #"LMAppleWatchCommunicationKey")
Even though it's never called by the extension, here is the exact receiving code of the extension which handles the incoming data, if it helps.
- (void)session:(WCSession *)session didReceiveMessage:(NSDictionary<NSString *, id> *)message {
NSString *key = [message objectForKey:LMAppleWatchCommunicationKey];
if([key isEqualToString:LMAppleWatchCommunicationKeyOnboardingComplete]){
BOOL newOnboardingStatus = [message objectForKey:LMAppleWatchCommunicationKeyOnboardingComplete];
[[NSUserDefaults standardUserDefaults] setBool:newOnboardingStatus
forKey:LMAppleWatchCommunicationKeyOnboardingComplete];
dispatch_async(dispatch_get_main_queue(), ^{
for(id<LMWCompanionBridgeDelegate> delegate in self.delegates){
if([delegate respondsToSelector:#selector(onboardingCompleteStatusChanged:)]){
[delegate onboardingCompleteStatusChanged:newOnboardingStatus];
}
}
});
}
}
Before including this onboarding-related code, my WatchKit extension was tested by over 100 people, without any troubles. I am using the exact same custom error dialogue that I was using before, just with a different string. I cannot for the life of me figure out what is causing this crash, and the ambiguity of it has given me very little to work with.
Any help would be greatly appreciated. Thank you very much for taking your time to read my post.
Edit: I just tried creating a symbolic breakpoint for exit(), which is never hit. If I call exit() myself, it calls the breakpoint, so I know the breakpoint itself is working.