This patch fixes a bug introduced into the level editor in v1.2.0. After placing a respawn beacon actor into a map, the editor would refuse to open said map and show an error message "Failed to load <map_name>". This is now fixed, and any affected maps can be opened again without any data loss.
We're really sorry about any inconvenience caused by this issue! Thanks to community member CyberOmen for bringing this to our attention.