Unable to download complete file via a shared link

Hey guys.

Lately I discovered a weird issue with my Nextcloud server (NextcloudPi on RP3B).
So, I have two .mkv files lying on my server. One is 5.8GBs and the other one is 4.7GBs. Whenever I try to download one of the two files via a shared link that I created, Firefox informs me that the file I’m about to download is ~530MB large, which as stated above, is incorrect.
However, when I logon to the server normally, without using my shared link, I can download the entire file just fine, and Firefox shows me the correct file size for the download.

So, why is it that I cannot download the entire file via my shared-link, but just fine when I logon to my server normally?

Is there something I forgot to set correctly in the settings?

Any help is greatly appreciated.

EDIT:
I found out that even though it shows me the correct file size for the download when I’m logged in, it still only downloads 500MB. So, the problem is the same in both scenarios

There were a few issues with php and large files on 32 bit systems. Not sure if that is really solved, it potentially creates problems with anything larger than 2GiB. If you find anything below works fine, it is probably this issue.

Perhaps try to connect via native webdav as well (link can be found in the file app, as client you could use winscp). What size is shown?