RIB (Royalty Interest Burdened)

Can someone tell me about RIB interest? The operator says it’s Royalty Interest Burdened but doesn’t know what it is burdened by. This interest had delinquent taxes at one time, but the operator says the burden isn’t related to the tax warrant. Could it be a reference to royalty interest burdened by an NPRI (non-participating royalty interest)? If not, what else could it be?

Ir could also apply to and OverRiding Royalty Interest. (ORRI) That is taken out of the Working Interest owner’s share.

Thanks. Some of the leases are RI, and others are RIB, so it seems more likely to be burdened by an NPRI than an ORRI, but you bring up a good possibility. Thanks.