914 was the last "measurement" (it was actually extrapolated based on 700 mb found at 2360 m). 908 mb was in an earlier "raw-data" message that didn't make it to an official Vortex Data Message.
The 908 mb pressure was from a dropsonde in the eye. The 914 mb pressure was extrapolated at a later time, which I guess is why NHC is using that number in their advisory.