This one is up there on the strange NS defects list - I've got an account using search.lookup to join from one custom record (Record A) to another (Record B) to get a value on the joined record (Record B). However, the value returned from Record B is wrong. It's somehow joining to an unrelated Record B record and returning the wrong value. The unrelated Record B record happens to have the same internal id as the Record A record (that's the only pattern noticed). Reproduces in Prod and SB, but not in NS's copy or other accounts.

does the matching search do the same thing?

Nope, at least not when creating a search via the UI

sounds weird, do you get the same behavior using nlapiLookupField in the browser's console

Do you have any kind of summary on the search? I've seen that produce weird results, especially with anything involving math

@Kris Wood Nope - I've seen this issue in two production accounts and two SB accounts so far. Posting more details the channel to see if anyone else can reproduce this in a prod account.

I've seen it before on joins but don't remember the resolution