Was I victim of a server-side cheat?

This happened to me last night. It felt like cheating but I wasn't sure, until I noticed the packet loss. All night I had fine connections. The moment I hit this anonymous Gibby for damage, I get massive packet loss on the server side.

This renders the game unplayable. I couldn't run away. The team got wiped. It looks like my teammates were caught in the open; were they stuck and unable to move like me? I couldn't shoot my ult which just went off in front of me, and it looks like my Caustics ult missed the window - did he have the same problem?

Is it just a coincidence that the server had a meltdown at the moment, something I've never experienced before in thousands of hours of play, or have people found a new hack? A hack is extreme and unlikely, but also inevitable seeing as cheaters are always evolving new techniques. The network behaviour here is unlike anything else and the usual server or client issues.