Disappearing iMessage after powering on iPhone 16 Pro

I haven't spoken to this friend for 2-3 weeks now and I've had instances where my phone would run out of battery while I'm watching Youtube. But this time after waking up after 6 hours, I charged my phone and turned it on, received a push notification from iMessage that had her email address as a contact instead (I manually added it to her name in my contact), so the push notification from imessage upon turning it back on look like this:

iMessage

heremail@gmail.com

Did she text me? Like I mentioned, this is the first time happening. I opened the notification and there was nothing in my inbox.

Did the message disappear? Is that possible?

I've read numerous amount of posts where they've had the same issues but never a solution in how to recover the lost/disappearing message.

This has been bothering me all week, and I can't message this friend for a while. Kindly help me please.

Thank you

[Re-Titled by Moderator]

Original Title: Received an iMessage push notification from a friend after powering on 16 Pro, but after I opened it - it's not in my inbox?