CEQP is an MLP and should only issue a K-1 according to their website. Any Unrelated Business Income is reported on the K-1. Should have no 1099 issued.
Same with BKEPP and SPLP-A.
Strange. I have been dealing with MLPs, but just the units as a limited partner, for 15 years and never got anything except a K-1. Whoever sent the 1099 I would call their investor relations dept and ask what it's for. Maybe it has something to do with a distribution from outside the MLP like a corporate holding?
Sorry I can't help more.
Please let me know what you find out though, as now you have my curiosity up.
Cheers,
Tony