A discussion related to this was already under way in this thread: https://community.logos.com/forums/p/94588/657763.aspx#657763
Since then, I ran into another problem that highlights the extent of the issue. I was reading a book that mentions Sifra and Sifre. Since (1) I was not familiar with these (2) There were specific references and (3) They are referred as Tannaitic and I am trying to have relevant primary sources for biblical studies, I sought to find whether I had them in Logos. Apparently not, since the few references I find do not work. So I wrote a post to ask the question to other users. In their answers, I find allusions to resources I HAVE that did not show up when I did this search (compare the left with the right):

The KEY benefit of Logos as an electronic resource and THE selling point of upgrading is the FEATURES and DATASETS. We can save so much time we are told by using this or that tool. Sure. But when resources are not properly tagged, and I mean not the occasional typo, but whole resources; when indeed getting resources out is prioritized over getting them right and the flow of new resources never stops, can I have confidence that what I find through Logos features is reliable? When I search Dead Sea Scrolls for specific data, will I be missing important data because tagging is incomplete? When I think I have done the research, can I affirm anything (publish anything) with any confidence? Do I need to read again all the resources myself in order to double-check and if so, what is the point of the features?
I am concerned here, really concerned.
(As usual, I would ask those people who think that their mission in the forums is to come along and say it ain't so or it ain't so bad or come to the rescue to perceived attacks on Logos, to please avoid hijacking this thread).