I am a founder, initial registered agent, and an initial board member of a nonprofit corporation. I do not now serve on the board, nor does the board follow the bylaws of this 501(c)(3). Am I in any way responsible for unfiled taxes or anything else that may go wrong in the future?
In general, once you resign all of your positions of responsibility with a nonprofit organization you should not be liable for failures occurring in the future. If tax returns were not filed on your watch, or if negligence occurred or people were injured while you were in a responsible position, you could possibly be brought back into the situation. But a complete disassociation from any responsibility within the organization will normally sever any liability for wrongdoing thereafter.