How do I stop Siri from abruptly closing all the time while recording text messages on my iPhone?

I’m wondering if it is impatient and if I just stop for a fraction of a second it just closes arbitrarily or perhaps it doesn’t like how slow I’m speaking and it just shuts down. It seems like Siri should be asking me “are you ready to send this message” before just shutting the app down before I’m finished.

[Re-Titled by Moderator]

Original Title: Often times when I ask Siri to send a text message it will open and start to record my message and within a few seconds the whole thing crashes and disappears. This happens frequently. Apple Care doesn't seem to know how to fix it.