Google Docs Making Unsecure Copy

I am using Cryptomator with Google Drive syncing between my Windows 10 desktop and Android device. From the Windows desktop, I put an rtf file in the Google Drive vault. Then I went to the Android device, unlocked the vault, and edited the rtf file.

What seems to be happening is that when I edit a vault doc with Google Docs writer, it makes a copy of the rtf document and saves the edited document in a folder outside the vault. When I lock/close the vault, the copied file remains and can be opened and edited in the Docs app. If I reopen the vault and edit again, the Docs apps creates a second copy, and so on.

My intention is to use Cryptomator to unlock/open files only when I am using them so that they can’t be viewed or opened at other times by other apps on the device. Google apps stay logged in all the time, and I hoped to use Cryptomator limit device access to sensitive files. Is that the way it is supposed to work?

As far as I know, if you save a document with Google Docs writer, it is automatically saved (unencrypted) online.
As Im not on android I can only make a suggestion:
Try “share file with” -> “Cryptomator” do safe the file in the vault.
Google Docs writer does not have a direct integration into other apps like cryptomator, so cryptomator does not know if you want to safe a file with a 3rd party app. You have to push the file into cryptomator instead of saving it via the app you are using to edit the file.