Tk-nuke fails due to core.python.tank.pickle.dumps error on diacritics in user name

Pipeline Integrations
1

A user can launch Nuke 13.0.3 via tk-nuke v0.14.1 and Desktop, but the Shotgrid menu is missing. The same launcher works for everyone else.

After some digging it turns out that pickle.dumps in core.python.tank fails with the umlaut in his name.
pickle.dumps("ö")

In [30]: pickle.dumps("ö")
---------------------------------------------------------------------------
UnicodeDecodeError                        Traceback (most recent call last)
<ipython-input-30-b11ebd35d121> in <module>
----> 1 picklek.dumps("ö")

/projects/SG_CONF/xxx/install/core/python/tank/util/pickle.py in dumps(data)
     44     # See https://docs.python.org/2/library/pickle.html#pickle.HIGHEST_PROTOCOL
     45     # Decode the result to a str before returning.
---> 46     return six.ensure_str(cPickle.dumps(data, **DUMP_KWARGS))
     47
     48

/projects/SG_CONF/xxx/install/core/python/tank_vendor/six.py in ensure_str(s, encoding, errors)
    897         s = s.encode(encoding, errors)
    898     elif PY3 and isinstance(s, binary_type):
--> 899         s = s.decode(encoding, errors)
    900     return s
    901

UnicodeDecodeError: 'utf-8' codec can't decode byte 0xf6 in position 1: invalid start byte
2

This does seem to be the correct unicode code:

Maybe the string was produced in utf-16.