There is a bug template to follow if you want to report a bug. It involves sharing more information so the problem can be found. I’ve moved this to Help.
My first guess is you are using a cloud syncing tool (or worse, 2 mixed cloud syncing tools) and getting sync conflicts. Can you share what OS, and what version of Obsidian, and what cloud tools you are using.
But otherwise, if you hadn’t skipped the bug template, there is a link to the basic troubleshooting steps to follow: “Please, follow the Troubleshooting Guide before answering Yes.” There are some steps to try there which might help.