Can't get ex to stick to custody schedule

She's been picking them up 30 mins to an hour late almost every Friday for the last month. I've texted, called, asked nicely. Nothing changes. It messes with my plans and the kids get confused. My lawyer said to document it but I'm wondering if I should just let it go to keep the peace. Any of you deal with this? I don't want to be that guy always complaining but I also feel like I need to protect my parenting time.