sphinx_rtd_theme is not getting applied on the ReadTheDocs builds but local builds work fine
ReadTheDocs doesn't purge the build directory on every new build. I fixed it by manually cleaning all temporary files from ReadTheDocs:

all build directories
created content from autoapi plugins

After that, my modified RTD theme was used for new builds.
To do so I added a tag detection in conf.py. If my tag is set, it does a cleanup. You can set user defined tags in the ReadTheDocs web UI.
I am facing a strange problem. I added latest sphinx_rtd_theme files on to my project and did the required theme overrides (including the well-known text wrapping within the tables).
The local build works absolutely fine. But it was pushed to the master, the theme goes back to very basic and it is not getting applied. I tried manual builds but still I could not trace the root cause and the workaround.
By master, I mean the builds that are created on the ReadTheDocs website (account).