TPS74801: Vout range limitation of 3.6V

Part Number:TPS74801

Hello,

What is the reason for the limitation of 3.6V Vout max in TPS748? (ABS max looks allow up to Vin+0.3V)
If we use with Vout>3.6V, what could it happen? (for example, Vin=4.5V & Vout=4.2V)

Thanks in advance.
Shinya Sawamoto