I will need more details on how you set the Culture manually in the app. It could be really helpful if you could send us a sample project where the issue is reproduced. Please open a support ticket and attach it there, as in the forum only image attachments are allowed. An alternative is to share the code you use here, however, having an actual sample will be very useful for us.
Also, please note that by default the Calendar control uses the device culture. If you want to set another culture manually, you need to create a custom renderer
and use the following code:
For more details how to achieve this, please refer to the link below:
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