Sealant coming off flange pipe transition to tank
I was looking down my toilet and saw some tp hung up on something. Used a stick to dislodge and noticed it was hung up on a loop of caulk that was almost detatched. The toilet in my 05 Safari is raised on a box. The flange assembly has a black pipe that goes straight down about 8 inches and it appears to terminate inside a wider tube slanting down to the tank. This is where the caulk is. Using a mirror and flashlight, I looked the "transition" from underneath and saw a grey, seemingly flexible seal to close the gap between the pipes - like a telescope as if to promote movement. The caulk was apparently put there to cover that gap, but is now 90% pulled away.
I am hoping someone could explain this design and provide their opinions whether or not I need to remedy or leave be. I suspect that grey seal is designed to do a job and the caulk might possibly be redundant.
I removed some 8 screws holding the flange to the floor, but was unable to budge it. Not sure how that comes out as well.
2016 Ford F-250 Lariat 6.7PSD