Display issue with python 2.7 (archlinux)

[julmon]

I'm facing strange issue with python 2.7 (2.7.15) on archlinux:

I can reproduce this with python 2.7.11, 2.7.12, 2.7.13 and 2.7.14, still on arch.
While everything is fine with python 3:

Just tried on centos7 + python 2.7.5, it's fine too.

It seems window.addstr() does not display things correctly with colors, when I try with attr=0, ie: no color, spaces between columns are back to a correct size.

[julmon]

It's seems this is not directly and only related to python version.