iOS TTS Alex voice is treated like available when it's actually not

In my app I allow the user to change TTS voices and English Alex voice is one of possible options. However, there are some cases when it's treated as available when it's actually not. It results in pronouncing the TTS utterance with another voice.

To prepare the list of available voices I use next code:

NSMutableArray *voices = [NSMutableArray new];
for (AVSpeechSynthesisVoice *voice in [AVSpeechSynthesisVoice speechVoices]) {
    [voices addObject:@{
        @"id": voice.identifier,
        @"name": voice.name,
        @"language": voice.language,
        @"quality": (voice.quality == AVSpeechSynthesisVoiceQualityEnhanced) ? @500 : @300
    }];
}

To start the playback I use the next code (here it's simplified a bit):

AVSpeechUtterance *utterance = [[AVSpeechUtterance alloc] initWithString:text];
utterance.voice = [AVSpeechSynthesisVoice voiceWithIdentifier:voice];
[AVSpeechSynthesizer speakUtterance:utterance];

Cases when AVSpeechSynthesisVoice returns Alex as available when it's not:

1. The easiest way to reproduce it is on simulator. When I download Alex from iOS settings, the download button disappear, but when I press on the voice nothing happens. As a result it seems to be downloaded, however it can't be deleted.

2. In some cases Alex is dowloaded correctly and is actually available in the app, but when I try to delete it, it looks like it's not fully deleted. As a result it's treated as available in my app, but in iOS settings it's shown as not downloaded.

3. If the iPhone storage is close to the full state as much as possible and Alex voice hasn't been used recently, looks like it's being offloaded, so it's shown as available both in iOS settings and in my app, but in fact the utterance is being pronounced by another voice.

For all cases above in my app Alex looks like it's available, but when I pass it to the utterance it's pronounced with some different voice. Note that it happens only with this voice, I haven't seen such a case for others. Maybe this voice should be treated separately somehow?

from iOS TTS Alex voice is treated like available when it's actually not