Hi, guys!
I have the same problem on my installation (PHP 7.4 / IIS+FastCGI ) after upgrade RS to 9.8 from 7.x.
I think that problem may be relate to tus module in RS. This module realize upload multiple files and lost some parts of uploaded data - i found broken parts in temp directory on server. And this case also may relate to max available php-threads on server.
So, can I ask you for details of your RS installation, e.g. server platform? It may get me more data to research problem.
My next steps:
1. Check (and update) modules in tus directory
2. Check this issue on RS 10 :) but, this case need more time to prepare test configuration on my platform
3. Deep dive in tus config / php config and try to trace problem step-by-step
If problem still actual, please answer me. And I inform about my results.
WBR,
Dmitry
P.S. Joao, I setup and start using RS from same time, about 2010 :)