Hi Alain,
Thanks for using Syncfusion products
We have analyzed the reported issue (The datepicker shows up with a placeholder instead of using the input value attribute) with our sample. We are unable to reproduce the issue. Can you please check with the sample in the following location?
Sample Location: Sample
In the above sample we have used the code snippet which you have provided in the response. Kindly check with the sample. If still you face the problem, please revert us by modifying the sample based on your application along with replication procedure. Also, if possible please share the screenshot or video to showcase the issue. This would be helpful for us to serve you.
Please let us know if you have any queries.
Thanks,
Saranya.S