Cache.html not found after deployment on appengine

[Robert Hoffmann]

Every now and then when uploading an update of my GWT application to appengine, the uploaded app seems in an inconsistent state, i.e. the Module.Cache.html file is not found. 

e.g. App not working, Browser console says '/Module/C96DE337B74EEDDBD2CF70FC4C65827B.cache.html not found'

I wonder if the upload/compile process might be interfered by an open GWT-Dev-mode session (aka hosted mode), even though I don't touch the code or actively use it while deploying.

(Detail: I am using the kindleit mvn gae plugin in IntelliJ to deploy.)

(I found this stackoverflow post with the same phenotype but no theory regarding the cause: http://stackoverflow.com/questions/12114988/http-www-sakshum-org-sakshumwebgae-8cb611ac7a0b5b6be2c4c99a8ea4defe-cache-html)  

Now, I always deactivate the GWT-dev-mode-session before uploading to appengine and I had no problem so far. 

But I would like to know if this really was the problem to get my confidence back --scary when an update leads to a blank page ;-)