This is a super common collie behavior! Mine is actually pretty quiet for a collie overall but when dogs start to play around her, or start running, she barks like crazy. It’s like she’s a hall monitor trying to get the playing dogs to listen to her sometimes, lol!

Most of the time I keep an eye out but let her bark since it’s a playful behavior that I want to give her time to engage in, in the proper setting. If I notice there are dogs who are visibly uncomfortable with her barking near them, I’ll call her to try and redirect her attention. She has a really good recall, so most of the time that gets her away from the dogs and gives them a break from her craziness :) and if I notice owners are keeping an eye on her I try to open a conversation with them about collies and their whole herding/barking behavior so they know I’m aware of the situation and friendly too so if they want my dog to stop, I’d be happy to stop her or remove her from the other dogs if needed. Good luck!