We've had a lot of repeat "issues" being reported on the forums that can quickly be answered by looking at the Magic Guide "FAQ: WebHints & TreeShare for Ancestry".
There is a list of RootsMagic Specific Items not supported in the Ancestry API. Along with Ancestry Tree Items not supported when downloaded or updated by TreeShare.
One frequently reported issue deals with anything attached to the Primary Name on Ancestry. There is no place to display it in RootsMagic. This is because Ancestry has two areas it supports with only one area in RM for it to go.
RootsMagic has on the Person row the primary name, and the general notes, sources and media. The primary photo for the person is also stored there. On Ancestry they have a separate fact for the primary name with its notes, sources and media. Then Ancestry has the general person notes, sources and primary photo. At this point we are trying to fit a square peg in a round hole, and things do not come out pretty. When you initially upload your RootsMagic tree or add a new person to Ancestry we can send items to a field that makes sense on Ancestry. If you are trying to update after the person is added you will have problems getting things into the right place. In fact the primary photo won't even display on the RM side if you have it marked as such in the MediaTag. Remove the checkmark and now you can see the photo, but you can't add it as a primary photo to the person on Ancestry, it will become general media.
Development is aware of all these issues, we have worked hard to make things fit. What needs to happen how is a complete rewrite of this area of RootsMagic in order to support these separate areas of Ancestry.
If you see anything that matches what has been reported then you don't need to report it again.