GMT6: incorrect regions when plotting using EPSG:3031 (Antarctic Polar Stereographic)

**Description of the problem**
I have been trying to plot - first with pygmt and then with gmt6.4 antarctic data projected in EPSG:3031 (south polar stereographic with true scale at 71 south) and lat long data, and finding that when plotting using the epgs flag, the region plotted is not aligned with the region commanded, resulting in misalignment. This appears to work fine when using the "S" original syntax. Below shows the epsg output, -Js and -JS output, and green dots showing the corner coordinates used to define the region. Note that the true scale at 71 south is *not* a linear scaling, but is a non-linear deformation compared to true scale at 90.

Might be related to issue #4352.

**Full script that generated the error**

```
!/bin/bash

trap 'echo $LINENO; exit' ERR

X1=122.62152014692141
X2=109.40195764826689
Y1=-66.89884214580835
Y2=-65.03587792781053

outfile=stereo_test.ps

REGION=-R$X1/$Y1/$X2/$Y2+r

proj="epsg:3031/5c"
gmt pscoast $REGION -Ggray -Dh -J$proj -Bxag -Byag -B+t"${proj}" -K > $outfile
echo $X1 $Y1 | gmt psxy -R -J -Sc0.25c -Ggreen -O -K -N >> $outfile
echo $X2 $Y2 | gmt psxy -R -J -Sc0.25c -Ggreen -O -K -N >> $outfile

proj="s0/-90/-71/1:10000000"
gmt pscoast $REGION -Ggray -Dh -J${proj} -Bxag -Byag -B+t${proj} -X9c -K -O >> $outfile
echo $X1 $Y1 | gmt psxy -R -Js -Sc0.25c -Ggreen -O -K -N >> $outfile
echo $X2 $Y2 | gmt psxy -R -Js -Sc0.25c -Ggreen -O -K -N >> $outfile

proj="S0/-90/5c"
gmt pscoast -Ggray -Dh -J$proj $REGION -Bxag -Byag -B+t${proj} -X9c -K -O >> $outfile
echo $X1 $Y1 | gmt psxy -R -JS -Sc0.25c -Ggreen -O -K -N >> $outfile
echo $X2 $Y2 | gmt psxy -R -JS -Sc0.25c -Ggreen -O -N >> $outfile
gmt psconvert -A -P -Tg $outfile
```

**Full error message**

No error messages result.

**Actual outcome**

**System information**

* Operating system: MacOS 12.5
* GMT version (6.4.0): installed with homebrew