We have taken Monster Energy cans (usually take 2, 4packs for my wife) on every cruise we have been on with no trouble. Sailing out of Port Canaveral, Miami, Port Everglades, and Seattle.
Same thing with our Apr 27 MG sailing. I called support 2 days ago and the individual I spoke to was seeing the same thing. He put in a trouble report. Hope it gets cleared up soon.
Used the app, provided them the required information and it has been 7 days with no response. App says "verification still in progress" So much for 2 business days.