When you die during Nanamech's rumbling mode it will prevent you from using signal orbs for your other characters in the party. I am using controller and haven't tested it on mouse and keyboard but I doubt that it will affect it.
#[PC Client] Dying during Nanami Starfarer's Rumbling Mode while prevent you from using signal orbs
ivory gale
mighty token
I also experience this bug on pc, am also using controller