Traceback editing replication task

When I edit a replication task but make no changes, I get the following traceback upon pressing save:

Error: Traceback (most recent call last):
  File "/usr/local/lib/python3.8/site-packages/middlewared/main.py", line 137, in call_method
    result = await self.middleware._call(message['method'], serviceobj, methodobj, params, app=self,
  File "/usr/local/lib/python3.8/site-packages/middlewared/main.py", line 1191, in _call
    return await methodobj(*prepared_call.args)
  File "/usr/local/lib/python3.8/site-packages/middlewared/service.py", line 463, in update
    rv = await self.middleware._call(
  File "/usr/local/lib/python3.8/site-packages/middlewared/main.py", line 1191, in _call
    return await methodobj(*prepared_call.args)
  File "/usr/local/lib/python3.8/site-packages/middlewared/schema.py", line 972, in nf
    args, kwargs = clean_and_validate_args(args, kwargs)
  File "/usr/local/lib/python3.8/site-packages/middlewared/schema.py", line 930, in clean_and_validate_args
    value = attr.clean(args[args_index + i])
  File "/usr/local/lib/python3.8/site-packages/middlewared/schema.py", line 607, in clean
    data[key] = attr.clean(value)
  File "/usr/local/lib/python3.8/site-packages/middlewared/schema.py", line 373, in clean
    value = super().clean(value)
  File "/usr/local/lib/python3.8/site-packages/middlewared/schema.py", line 76, in clean
    raise Error(self.name, 'null not allowed')
middlewared.schema.Error: [large_block] null not allowed