Please add additional information to your question about the version of the Xibo Player software you are using and the hardware of the player. An excerpt from the log files (captured directly on the client when the problem occurs and the Logs sent to the CMS) will also help answer your question. → Check How to record logs for a CMS issue using Report Fault
Have you checked if all these criteria apply to your layouts? → Check My scheduled Layouts are not working? | Xibo Digital Signage
Do the clients have a consistent internet connection? What is the size, resolution, and bitrate of the videos? I had the problem myself where clients switched back to the default layout, but the causes were usually different - e.g. memory leak, media corrupt or not downloaded correctly, incompatible driver versions, or the media took longer than 4 seconds to load and were blacklisted by the Xibo Client.