MARQ Athlete - has anyone else got wrist injuries from wearing the Athlete during sports?

Nothing remotely like that. I can't even bend my hand far enough back to contact the button. I have had long runs - several hours plus with it a little loose at the start and found it uncomfortable banging against my wrist bone until I tightened it but never any marks, rubbing or anything 'weeping sores'.

Perhaps you new wearing it too loose and it's banging up against your wrist bone? This is a much heavier watch than your former 235 and thus more susceptible to moving around if insufficiently tight.

No issues here after long rides or runs (ie this weekend 5 hours, mostly road though).  Hard to compare to a 235.  That watch is a fraction of the size and weight.  Maybe you'd better off with the 945?  Not as nice looking but the buttons don't stick out as much,

I’ve done running, mountain biking, strength training, CrossFit and circuit training with my MARQ Athlete on and never had this. I do use the lock keys function when there’s a chance I could flex my wrist far enough to trigger a manual lap or pause the activity, but I’ve never had the band buckle or buttons dig in like you show. Like Philip mentions, I can only assume you have the band done up way too tight (unlikely as it’s simply uncomfortable to do this) or it’s too loose and is slipping down to where your wrist flexes. It should sit so the watch does not slip down over the bone that sticks out on the outside+top of your wrist.