Blender 2.82: Bug or feature? Mirror along global axis looks like mirror along local axis

Hi Blend@s!

I am modelling a character on the base of metaballs. As I stretched and rotated the balls, their lpcal axes are oriented differently from the global axes. Rotations cannot be applied on metaballs without losing their shape orientation.

When I tried mirroring the limbs this body

the result looks quite desastrous:

The right leg (left in image) looks mostly right (as the X axis has nearly no tilt), while the components of the right arm are totally out of place and orientation.

I set the centers of the metaballs to origin and mirrored along the X axis globally. There is no visible difference to mirroring along the X axis locally. Any suggestions?

Best regards
Burkhard

(To be precise: The X axes of the legs were not tilted, so the result is exactly what I expexted.)