Create a tube
right click -> Cylinder -> Gear icon
click "tube" -> OK
Now two ways to see this bug.
1.
Select all the up-facing faces
Extrude Y up
Loop select inside and outside middle seams
Loop cut
There is an undeletable face inside both ends of the halves.
2.
Select the top faces
Extract up
There is an undeletable face in the center.
right click -> Cylinder -> Gear icon
click "tube" -> OK
Now two ways to see this bug.
1.
Select all the up-facing faces
Extrude Y up
Loop select inside and outside middle seams
Loop cut
There is an undeletable face inside both ends of the halves.
2.
Select the top faces
Extract up
There is an undeletable face in the center.
I'd rather live with false hope than with false despair.