I checked the Mu Cep light curve - no observations before 9/2012, and the map is not correct at all?
The star you are looking at is MU Cep (M-U), not miu Cep. The data currently in that light curve are mislabeled and are moved to miu Cep as needed. Those have probably come in via reports since the last time data were moved over, and will themselves be moved shortly.
To look for observations of (greek) mu Cep, please use the name "mu. Cep". Likewise, observers should use "mu. Cep" or "miu Cep" when submitting data. The naming situation with Greek-lettered star names is described in this write-up by Elizabeth Waagen.
Thank you, Matthew.