At first, we were sending an already transformed file to DXC for the integration environment. Then, I changed this, so that we send web.integration.config as well. The transformation never took place and support couldn't figure out why. In the end, we reverted our deployment process to do the transformation and send an already transformed file.
So, my question is as follows:
Our build server transforms web.config and deploys the transformed file to the integration environment, together with Web.Preproduction.config and Web.Production.config which contain environment specific configurations.
Yes ours is the same as Dejan, when using the pass portal or the service desk is doing deployments these files get transformed. Theres a full guide here https://world.episerver.com/digital-experience-cloud-service/development-considerations/environment-configurations/
As far as I'm aware, transformations only apply when moving between environments rather than deploying directly to an environment so the transform would never be applied to the integration environment. As the guys above have noted, your original deployment mechanism was the correct one - deploy a version to integration with the transforms already applied and provide transforms for preprod and prod which will apply as the site is promoted through the environments.
Sorry I misread, after seeing your comment. We running out integration transform file directly in our VSTS release build and deploy that package via an the Azure API, therefore it's the build/release system transforming and deploying to Integration. I don't think there's anything that happens on Integration like Pre Prod/Production as Paul says as these do not going through the deploying processes that Episerver use.
Wow. I logged into answer this and it looks like I'm a little late to the party.
What they all said