ROTH Sale

[Foolishtom]

I sold an entire position in an MLP &I transferred the entire proceeds to another ROTH IRA.

I recently received a 990-T for the Roth Ira. The K-1 lists it as a ROTH account not under my SSN. The tax return has a substantial tax amount due, calculating the entire investment as UBTI. Not sure how that is possible since the amount recovered is less than the original investment?  If I only recover what I invested how would that be considered excess UBTI? 

I may be way off base on the UBTI question and appreciate any guidance. 

Thank you,

Tomfoolery