I am having a hard time with this one.
How can the church say we know infallibly Mary was assumed to Heaven, we just don’t know if she died first or not? If you had enough evidence on the assumption to know it happened - wouldn’t you know if she was dead or alive?
And, you can believe either she died and was assumed, or was assumed while alive - it’s your choice, and can still be Catholic. But if you don’t believe there is sufficient evidence of the assumption you are not allowed to receive communion, that’s not your choice, you are not Catholic?