John - I searched through some of the GIT issues and commit activity for Cura 2.7-3.0 (the Lulzbot release is presumably based on 2.6, so this is “future stuff” for it). I found a couple of discussions regarding z-offset. My conclusion from what I read was that:
(1) At some point, 2.7 perhaps, an initial layer Z-offset feature was added;
(2) As of 3.0, it wasn’t working (perhaps never worked in 2.7?);
(3) After some discussion, it was decided to remove the feature rather than fix it; and
(4) There is an open request to add “first layer flow %”, so that a flow >100% can be specified to help with first layer adhesion.
At least that was my conclusion from the discussion – there could be other feature requests / pull requests that I didn’t find in my search, so that may not be the whole story. But my takeaway is that there won’t be a “z-offset” coming anytime soon, rather there will eventually be a feature to increase flow on first layer instead.
For now, it seems the only way to address it is with G-Codes.