Using a Spectre Flare where a block is low enough to activate it near yourself where you can reach and hit yourself will kick you out of the server with the message:

"Connection Lost

Attempting to attack an invalid entity"

I can also break blocks which i'm not sure is intentional. Maybe the other bunch of mods i have installed may mess with the spectate function. However spectating a Spectre using a Spectre Bound Spyglass doesn't allow me to break any blocks or hit entities like it should work...