Text messages being resent from February, in November

I first learned about this in the Google FI subreddit here https://www.reddit.com/r/GoogleFi/comments/dszauf/unexpected...

I was one of the people that received a message, just before 4am ET I received a message from someone I am not on speaking terms with and replied in a fashion one would expect for dealing with such an individual. Yay fun. Someone in another thread in that sub had reported they received a message from their ex calling them babe, and also replied.

My question here is, why is there some server out there that is storing messages from at least 4 carriers from 9 months ago and resending them.

I assumed carriers kept our messages for a certain length of time, and that one or more government agencies might store them indefinitely, but why is some random server out there holding onto messages for 4 major carriers for 9 months and as configured in some way that allows it to resend those messages NINE months later?

Forget the security implications of this, what about people that received messages from a friend/family member/co-worker/loved one that has since died like in the article:

>one person said they received a message from an ex-boyfriend who had died; another received messages from a best friend who is now dead.

Can anyone familiar with this part of the communications industry speculate on why such a thing is even possible or shed some light on just how long these messages might be stored on such servers?

The conspiracy theorist in me says that unnamed "vendor" is a 3 letter agency that had a bunch of messages drop into a dead-letter queue or similar and something caused them to all be re-processed... a la Room 641A (Yes I know in Room 641A they weren't in the middle but just saving off a copy but still).

better headline: Across major US carriers people received text messages sent Valentine's Day

Its not clear that the messages are being resent. They appear to being delivered for the first time.