You have 10k of Physical torque and evident reasons that states you have an issue.
Where this is emanating from is likely the well not the top drive.
As it should overheat or something ( ie thrust bearing) etc will quickly fail under this type of abnormal load I’d my view.
Run a surface tests then a similar test after BHA has been run.
Then check torque and drag trends every 10 stand to give us a pattern of evidence to work with.
Is this simply a higher consistent torque you are observing.
Is your drag higher than normal ( vs. Expected string weight in mud?)
Or is it a variant fluctuation torque?.
By Hoo much?
What exactly are the numbers you are observing at TD depth and at the shoe?
As stated by other do something tests at different RPMs and collect the evident data.
What does your torque drag model state? based on survey data?
When you trip out from the shoe unlock the swivel are you observing the string turning anti clockwork wise as you pull out of hole more than normal? . Again all indicators may be poor wellbore cylindricity and: or cased hole quality issues? If you onbserve same effect in open and cases hole. That could be the source of abnormalities of what you are observing?
if you don’t have surveys . You could drop a multi shot on trip out from casing shoe on next bha trip out? Then run your torque drag model based on results obtained.
What steel are you getting back from the shaker at the magnets? This could be indicative of wellbore tortuously?
Are you collecting the steel and measuring casing wear daily during drilling?
How much are you observing?
Because You could have a spiralled doglegged casing is your well pointing to the reason for your discrepancies.
Was the last casing properly centralised?.
Mud type? Solids content? Eg Silicate mud will give you extremely higher torque in even a vertical well in 81/2 in hole vs previous 12 1/4 in section.
Torque and drag tests as stated should show a trend to indicate it may be a mud problem if you are not seeing still at shakers etc.,
All suggestions of how to further investigate your evident problem.
Finally when was the last time the torque gauge was calibrated and checked? I would get the mechanic to verify this is also not the problem.