Ok, looks like the dists need to be constructed like this:
...
comp_dists=[
pm.Bound.dist(pm.Normal.dist(mu=1.0, sigma=upper_sig), lower=1.0),
pm.Bound.dist(pm.Normal.dist(mu=1.0, sigma=lower_sig), lower=0.0, upper=1.0),
...
Ok, looks like the dists need to be constructed like this:
...
comp_dists=[
pm.Bound.dist(pm.Normal.dist(mu=1.0, sigma=upper_sig), lower=1.0),
pm.Bound.dist(pm.Normal.dist(mu=1.0, sigma=lower_sig), lower=0.0, upper=1.0),
...