webdav expected filesize error

Expected behaviour

Upload large files

Actual behaviour

always breaks off at approx. 500 mb

Steps to reproduce

tested different files...

iOS version

12.1.3

App version

2.22.8

Server configuration

Operating system:
Ubuntu 18.04 LTS

Web server:
Apache version 2.4.29

Database:
MySQL version 5.7.25

PHP version:
php7.2

Nextcloud version: (see Nextcloud admin page)
15.0.2

The problem exists only in the IOS APP. everything else works without errors...

[webdav] Fatal: Sabre\DAV\Exception\BadRequest: expected filesize 592271553 got 521281536 at <>

0. /home/cloud4/public_html/apps/dav/lib/Connector/Sabre/Directory.php line 156
   put(null)
1. /home/cloud4/public_html/3rdparty/sabre/dav/lib/DAV/Server.php line 1096
   createFile("Video 19-02-01 21-02-57 0539.mov", null)
2. /home/cloud4/public_html/3rdparty/sabre/dav/lib/DAV/CorePlugin.php line 525
   createFile("Video 19-02-01 21-02-57 0539.mov", null, null)
3. <>
   httpPut(Sabre\HTTP\Reque ... "}, Sabre\HTTP\Response {})
4. /home/cloud4/public_html/3rdparty/sabre/event/lib/EventEmitterTrait.php line 105
   call_user_func_array([Sabre\DAV\CorePlugin {},"httpPut"], [Sabre\HTTP\Requ ... }])
5. /home/cloud4/public_html/3rdparty/sabre/dav/lib/DAV/Server.php line 479
   emit("method:PUT", [Sabre\HTTP\Requ ... }])
6. /home/cloud4/public_html/3rdparty/sabre/dav/lib/DAV/Server.php line 254
   invokeMethod(Sabre\HTTP\Reque ... "}, Sabre\HTTP\Response {})
7. /home/cloud4/public_html/apps/dav/appinfo/v1/webdav.php line 80
   exec()
8. /home/cloud4/public_html/remote.php line 163
   require_once("/home/cloud4/pu ... p")

PUT /remote.php/webdav/Video%2019-02-01%2021-02-57%200539.mov
from 192.168.10.1 by Florian at 2019-02-01T20:06:13+00:00

Start with the PUT request and the error at apps/dav/lib/Connector/Sabre/Directory.php line 156, then follow the WebDAV entry point in apps/dav/appinfo/v1/webdav.php and remote.php. Reproduce a large upload from the iOS app using the listed versions and compare the expected and received sizes; done means the upload completes without the filesize mismatch.