I am on the latest version of Lightroom and I noticed that under Lens Correction my lenses will show a message:
"Built in Lens Profile applied". But if I choose Enable Profile Corrections and select the correct lens there, then the photo looks different.
Am I applying double "correction" or is this choosing between the Camera built in Profile correction and the Lightroom profile corrections???
Let me correct this: Your embedded profile is for chromatic aberration only. So, you must not manually activate this.
However, you still need to manually enable the distortion correction if you want it to be corrected.
Note the difference in the info text on your post and the linked page.