There is an option in Verizon's system, iirc it's called gsa priority em access (might have changed the name), that needs to be enabled for their network to bypass the throttling triggers and give the line primary SoE network access. If the option wasn't provisioned by Verizon then the line would be throttled. Verizon has some weird quirks with their provisioning portal, sometimes feature updates fallout or instances where non compatible features will auto remove from lines and some features need to be added manually on their backend by a csa.
I've had to deal with Verizon's shit on the daily for clients over the last decade and used to purchase the majority of equipment and services for DOI / BLM before they ended the contract with a former employer. I've set the same feature on over 5,000+ lines myself and have seen the error between 400-500 times.
This is why I don't trust the city / county officials statement and insinuation that Verizon throttled intentionally due to net neutrality reasons. Sounds like a legitimate provisioning error by Verizon customer service based on the article description.