Auto Chmod inside directory

Hello, I use Nextcloud to keep important files synchronised between my computers. This works without any problems, but the folder on the desktop is treated as 777 after every file change. It affects all folders that are below Public/fr4, which is strange, it is kept in sync with a second machine and there (Public/he) this does not happen. How can I find out why this is happening? Are there any possibilities here? It is not the future to use find  . -type d -exec chmod 755 {} \; Thank you. Silvio