That’s really odd. The controllers are only remote controls to the system running on the speakers, there shouldn’t be any difference playing from any controller. 

I would recommend that you submit two system diagnostics, one from your daughter’s iPad, and one from your iPhone, and contact Sonos Support to discuss it.

I usually suggest the phone folks, they have more tools available, but are only available Monday through Friday during business hours. Twitter support folks are available 24/7.

There may be information included in the diagnostics that will help Sonos pinpoint the issue and help you find a solution.

And as a random thought, not that I’m sure it would make a difference in this case, I’d check to be sure that both devices are running the same version of the Sonos software. 

Thanks Airgetlam. I did the system diagnostics yesterday and contacted Sonos Support via Facebook Messenger but they don’t seem to respond. I’ll try Twitter until the phone support opens.

Sonos doesn’t list the Facebook option on their contact page, so I’m unsure if it is a valid option at this point. The twitter information is there, though, I’d expect you’ll have better success there.