This behaviour is as intended, because the whole idea of that operator is that the edges coefficient is an LM, and the offsets, if any, should be on the level of the LM coefficient. However, the user might not realise that, so an error (probably) should be raised.
This issue was exposed by https://github.com/statnet/tergm-private/issues/147, in that the
N()
operator does not propagate offsets.This behaviour is as intended, because the whole idea of that operator is that the
edges
coefficient is an LM, and the offsets, if any, should be on the level of the LM coefficient. However, the user might not realise that, so an error (probably) should be raised.