I thought he's still in his Shackle Regalia mode. Because if it is, at least he can move freely now.
If you want to be technical, both Gamagoori himself the onscreen text when he transforms calls this form "Shibari no Sou Aratame" which is Shackle Regalia MK.II but I don't even know if we have a Shackle Regalia tag here so I'm just going to call it Scourge Regalia for the time being.
Probably also mean he has a yet stronger battle mode of the armor which would be the real Scourge Regalia MK.II