LLC 3 partners K-1

Not sure if I'm being too picky. New client provides me a K-1 from an LLC with 3 members. A small loss in box 1 some royalties and distributions. The K-1 was all that I received, no attachments, nor was box L regarding capital account information completed. I requested appropriate attachments and informed the client that section L regarding his capital account was blank. He told me all income was passive and the LLC hardly made any money and no capital. He mentioned he'd never been asked for that information. Since I always request the prior 3 years tax returns from new clients once he gave those to me I saw the preparer (HRB) recorded the loss amount from the initial year K-1 and provided a beginning basis amount. That was the year the LLC was organized. I'm thinking how would HRB know what to put as starting basis unless the client provided the information?

They might have just guessed or been wrong.

I once called an actual CPA about a situation with a clearly wrong partner basis worksheet and was told "That's what the software put there!" as if no one could be expected to review it or understand how it got there.

Instead of the dog ate my homework now it's the software..