UploadCollection with preflight cors requests does not work

[bluecking]

Hello!

I have implemented an UploadCollection control in my sapui5 application. When I try to upload a file via the "+" button, my browser sends a preflight request beforehand to the server. Interestingly, it sends an "Access-Control-Request-Headers" http header with these values:

I know how to permit request headers in the XS Admin Tool in general. However, the requested headers sent by my browser are dynamic. In this example the requested header is "filenamerequestid1485264452016", but if I try to upload another file it might be "filenamerequestidxxxxxxxxxxxxx". I know that the number behind "filenamerequestid" is the current unix timestamp in milliseconds. To handle these dynamic headers I configured my cors settings in the XS Admin Tool like the following:

However, doing so does not work. Is there anything I could do to solve this problem? Or might this be a bug in the UploadCollection control?

Thank you in advance!