AVCHD files will never be supported by Adobe until it becomes profitable. Until then they will spin and dance and tell you your computer processor is too slow, or you don't have enough ram or you have the wrong operating system or you have to transcode or buy some more software or hardware... Just like Avid.
I lost thousands of dollars with Avid and wound up throwing my Avid Media Composer in the garbage. Funny... there it seemed to fit fine.
Complacency and greed killed Avid and now it looks like complacency and greed have their sights on Adobe.
Remember: There is a season for all things.