Tufty 2040 display

I have just got a Tufty 2040 and have moved over some code that was running correctly on a a Display Pack 2 and a 2.8 inch Waveshare screen but have come across a few issues…

When using any pen type other than RGB332 the screen corrupts when rotated 90 or 270 degrees:

In RGB332:

Is this to be expected with the Tufty? Is it due to the parallel connection?

A second issue is that setting the backlight to anything less than about 0.4 turns the screen off completely, is this normal as well on the Tufty?