ya know issues, do it to much then issues, even a plant put into bloom can be returned to veg, just cut away the flowers and re-veg. Not recomended but in the right circumstances, benificial. (early bloom burn etc).
You will be fine... I had a timer completely DIE and fail on me and my flowering cheese accidentally got almost 20 hours of light before I noticed. It only happened once and I didn't see any ill effects.