It usually activates with firm pressure, but if it’s getting harder over time, maybe try recalibrating in the settings or checking for brake system updates., it could also be temperature-related.
Maybe the brake hold system is just getting used to your driving style. you could try giving it a quick reset or check if there’s an update floating around for the system.
It takes a solid push on the pedal to kick in, not just a gentle touch. That's a safety feature so it doesn't engage when you don't want it to. About it needing more pressure each time that's a bit odd. I haven't seen that myself. It could be how you're pressing the pedal or maybe something going on with the brakes. If it keeps happening I'd suggest getting it checked out by the dealer. It's probably nothing but it's worth being safe. Has anyone else noticed this?