This is a very complicated question that can only be answered after a review of all of the facts. It is true that a person may adversely possess a piece of land owned by a group of several homeowners even if the owners were jointly paying taxes. The homeowner will need to have adversely possessed the land in an open and notorious manner, continually and exclusively for a period of ten years. However, if the possessor did so with permission, then the possessor cannot obtain title through adverse possession. So, to the extent CC & R's or other HOA documents allowed these homeowners authority to use the common areas that use will not be considered adverse possession. There are several other factors that may affect this analysis. I would recommend reviewing your matter with a real estate attorney.
Commonly owned property is not exempt from adverse possession. However, there are ways to prevent that from happening, and the HOA should take action to prevent single owners from abusing common areas.
If you would like more information or assistance you can reach me at 206-842-7811 or firstname.lastname@example.org.
Thank you and good luck.