Not sure How the "No it does not" comment relates to either my quote of BigAl007"s. We all three agree you can utilize a 1.4x extender with the Canon EF 100-400mm on the 80D and still have AF access to 27 focus points. Maybe I'm missing the point of your post.
No, we do not agree. That is simply not true.
The 80D has 27 f/8 AF points with the 100-400LII & 1.4X III TC.
The 80D has 27 f/8 AF points with the 200-400L and 2x III TC.
With the ORIGINAL 100-400L and 1.4X III, it has one f/8 AF point.
With the ORIGINAL 100-400L and 1.4X II it has one f/8 AF point.
With the 100-400L II and and 1.4X II, it has one f/8 AF point.
There are only TWO lens/TC combinations that yield 27 f/8 AF points:
1.) 100-400L II AND 1.4X III TC.
2.) 200-400L and 2X III TC.
With ANY OTHER lens/TC combination at f/8, the 80D has ONE f/8 AF point.
I hope that clarifies the issue.