No chunked upload with iOS app?

Hi

I’m facing the problem that chunked upload on iOS app is not working … I wonder if this is just not implemented or if I have a problem in my configuration.

In the log on the server I get

where you can see, the uploaded number of bytes is less that in the attempt before. I have a few other attempts before with the same.

Nextcloud version: 16.0.3
Operating system and version : Raspbian Buster
Apache or nginx version (eg, Apache 2.4.25): Apache 2.4.38
PHP version (eg, 7.1): php-fpm 7.3

How can I check if the configuration on me side is ok? Anything to enable in the iOS app?