Yes, I tried to update an app today and actually encountered a very similar error:
STATE_ERROR.VALIDATION_ERROR, status: 409, title: Validation failed, detail: Info.plist value mismatch. CFBundleShortVersionString value of 1.2 does not match the value of 1.1.0 specified in the request.
At first, I created a new version in App Store Connect and named it 1.1.0. Apple didn't accept that, so I renamed it to 1.2. The same error occurred again after that. I tried it twice more after reloading the browser for App Store Connect and AI2. Then I increased the build version number to 5, and it worked. 
The whole thing is very strange.
