Plausible I guess. Essentially a denial-of-service attack from a new device connected to the network. The article doesn't give more details but a device in the network can ... send traffic into the network ... and a device connected to a high speed link in a network with many old legacy/slow devices ... could cause problems.

The router was apparently a Juniper router. L3Harris I guess buys them and install/configures/whatnot. They don't make them.