'night' mode is notably awful when used in conjunction with REGAL waveform update modes (the very thing that makes it look so nice and ghost-free when used normally

), because those waveform update modes are very much tailored for black-on-white. Since that's what the Aura & H2O defaults to, that would probably explain Glottis's experience

.
We've been seeing the same thing on the PW2 w/ KOReader [where we don't use the HW flag either], for what it's worth. (And, although I haven't checked, even using the HW flag wouldn't help. What would help is a waveform update mode tailored to that kind of thing, which is apparently
something that was introduced in the updated Kernels of the KT2 & KV in Kindle-land

).
Which reminds me that we should probably fall back to a non-REAGL waveform mode when using night mode in KOReader, before the slew of bug reports come in now that we've enabled REGAL-waveform modes on Kobos... (xref:
#1109).