He received a $267,000 loan from a friend to buy an RV. The loan wasn't disclosed on his ethics form. Then he didn't pay it back. At first he paid interest only payments and at some point he quit doing that. Rather than face the spectacle of having to sue a Supeme Court Justice, his friend forgave the loan in a handwritten note which also said only interest had been paid. Thomas also failed to report that on his ethics form. More troublesome is the likelihood Thomas didn't report the loan forgiveness to the IRS which would have required him to pay income taxes on the $267k.
I am sure Tom will be along any moment to insist Thomas not be given a sweetheart deal, deamand House Republicans start an impeachment inquiry, and demand that Justice Thomas to do jail time.