Error when using tfp.sts.Sum with StateSpace Components

Running this simple Example:

from tensorflow_probability import sts
local_ssm = sts.LocalLinearTrendStateSpaceModel(name='local',num_timesteps=30,level_scale=0.5,slope_scale=0.1,
                                                    initial_state_prior=tfd.MultivariateNormalDiag(loc=[0., 0.], scale_diag=[1., 1.]))
model = sts.Sum([local_ssm])

Gives the error ( in tfp version 0.17.0):

File "/usr/local/lib/python3.8/dist-packages/tensorflow_probability/python/sts/components/sum.py", line 462, in init
name='{}_{}'.format(component.name, parameter.name),
AttributeError: 'str' object has no attribute 'name'

Note:

The variable "parameter" in SS components are Python str. So this loop in /tensorflow_probability/python/sts/components/sum.py fails:

  for component in components:
    for parameter in component.parameters:
      parameters.append(Parameter(
          name='{}_{}'.format(component.name, parameter.name),  # FAILS  because 'parameter' is str for StateSpace components
          prior=parameter.prior, bijector=parameter.bijector))

Start with tensorflow_probability/python/sts/components/sum.py, especially the loop around line 462, and reproduce the reported example using sts.Sum with a LocalLinearTrendStateSpaceModel. Trace the StateSpace component parameters and verify that the example constructs the summed model without the reported AttributeError.