You should not ground the PP pin.
The complication comes during startup and initialization.
The PP pin is active on startup (default value for poscmp_enable = 1). If PP is enabled, and there is no position mismatch detected, PP will pant to output a logic high. If the pin is grounded, this would lead to a short and likely exceed the maximum current allowable for that pin and cause damage to the device.
A programming error may also cause the same result.
Instead, a better option would be to tie this pin to a pullup (as recomended) or leave this pin floating . PP can still be used as it is tied high or low internal to the IC, and leaving the pin floating while in tristate may slightly increase current consumption, but won't have a negative effect on behavior. Using a pullup is still the recommended method.