André, in these cases it is simpler if you post the plain GMT command. For example here I can’t really understand what python does with the above operation where a 4 and a 2 elements vector are added. This should be a undefined (error) operation, but apparently it isn’t.
Ok, first thing first … The focus is PyGMT but I use the same colab to reproduce the first error (note the problem is not pythonic). Doing in plain GMT:
gmt begin test png
gmt psbasemap -R-70/-50/-71/-60/-5500/3000 -JL-60/-65/-72/-60/15c -JZ5c -p-35/35 -B -Bza2000f1000 -BWseNZ
gmt end
The answer as to why the z axis is shifted is the metric combination (z) with the projection (-JL) “deforms” the geographic plane over the bounding box created in figure . So the axis will certainly appear to be offset from the point of the figure.