Lightning-Shrink is the default.
signals
The problem was that it was still there when I disabled it, & only worked after selecting Default.
However, it hasn't solved my problem, as I've noticed now that everything I'm converting is now worse than the original, mainly that the result of my conversions to h265 are with missing frames? Don't understand why it's happening, as I haven't made any changes to my settings since previous conversions, nor have I added any new software or upgrades to my PC, so I''m now totally confused as to what is going on?