Hello,
Please note that there are several limitations in Open Source version of ONLYOFFICE. First of all, there is a limit of open editing sessions (it is 20), as we can see on the screenshot, you have more than 20 open sessions. The 21st session will be opened with a viewer. That’s why there is no new content in the file saved. The second limitation is that document server uses only one core of CPU. Slow opening of the file can be connected with this limitation (furthermore there are more than 20 editing sessions opened). Please specify if your document server is installed locally or not. If you have problem with slowly opening files, you can send those files to us in private message or to support@onlyoffice.com