Bitwarden and MS Edge

If you’re asking about exporting (not “importing”), then yes, there were reports about this problem recently. As explained in this thread, the solution is to upgrade your Edge browser to the latest version, in which case the false-positive warning can be overriden by clicking the download icon and selecting the option to keep the blocked download. If you’re unable to upgrade the browser, or if there is a risk that doing so will log you out of the browser extension, then you can instead using the following work-around: in the Edge settings, configure the downloads settings so that you specify where each downloaded file should be saved to; then, when exporting your vault, while Edge is waiting for you to specify the file location, use Windows Explorer to open your Downloads folder and copy the just created temporary file to a different location (and renaming it to have a .json extension).

With regards to your broader question, no, it is not possible for Edge to change or delete your Bitwarden master password.

Some other possible explanations are that you are misremembering or mistyping your master password or email address, or that you are trying to log in to the wrong server (bitwarden.eu vs. bitwarden.com).