In LVP's core.lua file, after the line "frame:SetFrameStrata("BACKGROUND")" and before "frame:SetPoint(point1, UIParent, point1)" you could try adding
Code:
frame:ClearAllPoints()
No guarantees, I just saw this suggested elsewhere even though it's not been needed in the past and my addon certainly doesn't ClearAllPoints even for mutiple ViewPort size changes with Alt-Z. Unless it also has to do with timing as I don't make any adjustments until after PLAYER_ENTERING_WORLD.