We suspect that the problem might be due to the misplaced order of culture script file reference in your application. Please see to that the culture script files are referred correctly after the reference of web.all.min.js file in your script reference section. We were unable to reproduce the reported issue “Localization is not properly applied for Scheduler” at our end, therefore we have prepared the sample(includes Scheduler and Grid) for this which can be download from the following location:
In the above sample, Scheduler and Grid are rendered in German(de-DE) culture where month/day names are correctly localized. Kindly try with the above sample and if the issue still persists at your end, try to reproduce the error in the sample and revert else share the code example/sample (if possible).