This traceback is a bit difficult to copy. I initially missed the scroll bar in the pop-up window.

File "/usr/lib/python3/dist-packages/tryton/gui/window/form.py", line 477, in sig_new
self.screen.new()
File "/usr/lib/python3/dist-packages/tryton/gui/window/view_form/screen/screen.py", line 626, in new
record = group.new(default, rec_name=rec_name)
File "/usr/lib/python3/dist-packages/tryton/gui/window/view_form/model/group.py", line 405, in new
record.default_get(rec_name=rec_name)
File "/usr/lib/python3/dist-packages/tryton/gui/window/view_form/model/record.py", line 378, in default_get
self.set_default(vals)
File "/usr/lib/python3/dist-packages/tryton/gui/window/view_form/model/record.py", line 438, in set_default
self.validate(softvalidation=True)
File "/usr/lib/python3/dist-packages/tryton/gui/window/view_form/model/record.py", line 401, in validate
if not field.validate(self, softvalidation, pre_validate):
File "/usr/lib/python3/dist-packages/tryton/gui/window/view_form/model/field.py", line 135, in validate
self.set_client(record, value)
File "/usr/lib/python3/dist-packages/tryton/gui/window/view_form/model/field.py", line 490, in set_client
super(M2OField, self).set_client(record, value,
File "/usr/lib/python3/dist-packages/tryton/gui/window/view_form/model/field.py", line 157, in set_client
self.set(record, value)
File "/usr/lib/python3/dist-packages/tryton/gui/window/view_form/model/field.py", line 495, in set
if not rec_name and value is not None and value >= 0:

TypeError: '>=' not supported between instances of 'str' and 'int'

@pokoli: I have attached a list of installed packages matching 'tryton'.