I notice that some brush dynamics get messed up when rotating the canvas.

For example, select the Pencil 2B preset, draw a line, and it's a relatively thin line, as intended. Rotate the canvas 90, then draw a line and you get a thick line. It's as if the brush dynamics of the non-circular, long shape of that preset aren't oriented to the canvas as it rotates.

Must be fixed in master(development version), because I can't reproduce it.

What is you version of Krita, and your operating system?

It's fixed in 2.8.5. I was using 2.7.5 from debian.