Op Amp Voltage follower
Data sheet, page 5:


  Vicm Common mode input voltage range VDD + 1.15 to VCC - 1.15 V


You're trying to make it work VDD + 0 to VCC - 0 V; that won't do. This is just what is known as Latch-up behaviour.

You have a rail-to-rail output opamp. What you'd need to have is a rail-to-rail input and output (RRIO) opamp for this to work.