I don't mean not physically on her, but her not using it when she is meant to be looking after my child. I often notice her on her phone and DC nudging her and her saying one minute, etc. I work from home, so I tend to see what's going on and if I'm going past I do occasionally mention it but she claims that my DC is happy doing x, y and z so she thought she'd quickly reply to an email/text, etc.
AIBU to think this isn't okay?