Bug: Words on which Word Studies Can’t be run

I can find the word εἶπον (say) but not εἶπεν (speak) in Bible Word Study. Both are found in a search. I think the lemma is λέγω which is where I’d expect to see both forms.
Note: there are differing opinions re: the lemma – program functions appropriately.

Software version: 4.0c Beta 4.
Reported by Tyler Markkanen/MJ Smith.
Forum link: https://logos.vanillacommunities.com/forums/p/15703/119569.aspx#119569
Status: invalid