I did a search for Tax Court opinions with "interest shortfall" and found the fascinating story, told by the inimitable Judge Holmes, of "Boris Putanec [who] entered into a complicated and carefully structured CARDS transaction that he hoped would bring to life more than $100 million in losses. We can't grant him his wish. The deal is the stuff of tax wizardry, while the Code treats us all as mere muggles."

https://www.ustaxcourt.gov/opinions/2016/TCMemo_2016-221.pdf 

There's no OID going on here, but what you have may be just another variation on an old tax shelter.  Whenever I see LPL I know it's through a financial adviser who can do almost anything with almost anyone.  (Check out the fines and penalties they have paid, on their Wikipedia page.) 

If this client walked into my office, I would be reminded of the lyrics written by a Nobel Price for Literature winner:  ""Something is happening here/ But you don't know what it is/ Do you, Mr. Jones?"

I would look for a reason that someone would be reporting all that OID for seven years, just to end up with a loss in 2024.  Were there losses that canceled out the interest income?  Was he banking the ordinary income, knowing that it would turn into a capital loss that he needed to offset a large capital gain down the road?  I would be concerned about playing the role of "useful idiot" by putting on a 1040 the results of a scheme engineered by someone else.