Looks like you're making a mission site. Would you like help?
Problem is, you are using valid ufo type ('STR_CRACKHOUSE') with invalid trajectory (trajectories need at least two waypoints, 'MISSION_SPAWN' only has one). So game creates ufo, tries to assign trajectory and explodes.
You can set objectiveType to '3', specify site deployment in siteType and use nonexistent ufo type in waves:
(...)
alienMissions:
- type: STR_CRACKHOUSE
(...)
objective: 3 # change to '3' for mission sites
siteType: STR_CRACKHOUSE # add name of alienDeployment to use
(...)
waves:
- ufo: THIS_UFO_DOES_NOT_EXIST
count: 1
trajectory: MISSION_SPAWN
timer: 1000
objective: true
If you need multiple different random deployments for single alien mission, you'll have to use missionZones and negative texture ids. See Piratez for example.
Or you can keep it in line with rest of the mod and rename ufo:
(...)
alienDeployments:
- type: STR_CRACKHOUSE
(...)
customUfo: STR_CRACKHOUSE_UFO # use new ufo name
(...)
alienMissions:
- type: STR_CRACKHOUSE
(...)
objective: 0
(...)
waves:
- ufo: STR_CRACKHOUSE # there is no such ufo so game skips to mission site creation, and there is deployment with this name
count: 1
trajectory: MISSION_SPAWN
timer: 1000
objective: true
(...)
ufos:
- type: STR_CRACKHOUSE_UFO # rename ufo
(...)