A very annoying bug when you already add 2 connect iq data field, but when cannot replace with new connect iq field. the watch claimed I had fully booked the 2 connect iq data slots, even I already deleted all the data field pages. For me this happened when I duplicated my RUN ACTIVITY PROFILE.
The solution is to "Restore Defaults" inside the "Activity Profile settings" and FINALLY solved my nightmare..
Hope this helps for anyone encounter the same issue...