I am having the same issue with the 2018 update. Not only does it sit too low on the launch pad but the textures aren't as good as the originals from the Delta IV launch Vehicle 3.0. The old version
does actual work in 2016 and looks really good in my book as I go for the higher level of detail. The only thing is that the old one does not have an autopilot for the launch (built-in one just spins out of control less than a minute it to the flight) and the separation sequences need to be ironed out. The 2018 might be multistage for the launch but at the cost of replacing all the decent textures and correct construction...?
Because they are constructed differently, the ones that run from .dll files I don't know how to alter (as I'm not a coder) but I can use the .ini and config files. So trying to sort it myself is difficult.
I enjoy making/watching the launch sequences, and I'm building a catalogue of launchers in my orbiter so will just have to fly the Delta IV with a manual launch profile. This is all focused around the Parker Solar Probe Launch too.
Delta IV Launch Vehicles 3.0 (P.S.P.)
Delta IV 2018 (P.S.P.)
The Solar Probe 2005 on the Atlas V works an absolute dream...