The reference manual reads as those pins should be "w/o pull", however I measure the pins being pulled high during sleep on the bench.
The language in the reference manual is confusing (pasted below), because all three bullets imply the same thing, that the pins should be in high impedance state.
"All the IOs are in high impedance under reset. In low power modes (sleep and standby) the IOs are configured as follows:
- IO0 to IO8 and IO14 are in high impedance state
- IO9, IO10, IO11 are in input state w/o internal pull according to IO configuration
- IO12 , IO13 are in input state no pull"