Scheduled recordings won't take place while the box is in STB mode.
I'm afraid that means that if you've set the box to record something at, say, 8 o'clock and you're watching a Non-Freesat programme at that time, the recording won't take place. Similarly, if you've left the box in STB mode and put it on standby, recordings won't take place. The schedule shouldn't be erased as such, but recordings won't take place if the box isn't reset to Freesat.