I have discovered this also this morning. I sent a crew out to replace the radio and the same thing happened when the new radio attached. After turning the ethernet interface back on the problem stopped. This shut down the whole sector when this happened. I have not found any other mention of this except here. This needs to be added as a bug in release notes. My install is a similar situation where the SM with the ethernet disabled is a backup link in case of a failure on a primary.