With a sense of relief, Alex reopened the project in After Effects. To their surprise, the project opened without any errors. The animation was still intact, and the 3D elements were still moving.
When using ExtendScript ( app.project.item(1).layer(1).property.addProperty(...) ), you must use a valid property type string. after effects error asked to create unknown property of type
If the error happens without a project open, it might be a script. With a sense of relief, Alex reopened the