LAN server doesn't show up in clients unless net=host

Server seems to be starting ok but there's no way to connect to it from my android or ios devices. It doesn't show up in the "friends" tab at all.

If I set the docker to net=host then it works.

Docker arguments:
-e EULA=TRUE
--volume minecraft-data:/data
-e UID=1002
-e GID=1002
-p 19132:19132/udp

What's wrong?

Start by reproducing the LAN discovery failure with the listed Docker arguments and compare it with the working net=host configuration. Determine why Android and iOS clients cannot discover the server through the published UDP port; done means LAN discovery works without host networking.

Written by the indexing model from the issue text.