Umdns issues with OpenWrt 19.07.1

There appears to be something strange that's going on with umdns with the OpenWrt 19.07.01 service release. While umdns appears to be running fine, it no longer advertises the router. I have been able to reproduce this problem on a Buffalo WZR-HP-AG300h and Linksys EA8500, as well as TP-Link TL-WR703n, and MR-3020. 19.07.0 works fine.

By contrast, avahi appears to work fine (except for the much larger footprint).