It would not surprise me if "may issue" and "no issue" states repeal their carry laws as a result of a national carry bill becoming law, if that would somehow exempt them from such a law. I have not read HR822, so I only know the bare basics of it. Some people find loopholes for good reasons, some people find loopholes for bad reasons. It may be considered unconstitutional, but I could see a few states doing something like that, even if it keeps the issue in appeals court for a significant period of time, just to get their point across. The Philadelphia City council passed a measure that disallows nonresident carry permits in the city, even though the state of Pennsylvania allows them and the state law supposedly can not be superceded by a law from a lesser municipality, but they did it anyway.
I still worry about the federal government becoming involved in this area, because there are usually trade-offs or surprises that come out after bills are passed.