import bpy
class GregId(bpy.types.PropertyGroup):
    name: bpy.props.StringProperty(default="")
bpy.utils.register_class(GregId)
bpy.types.Object.my_collection = bpy.props.CollectionProperty(type=GregId)

TEST_VALUE = 5

cube = bpy.data.objects["Cube"]

for i in range(TEST_VALUE):
    new = cube.my_collection.add()
    if i == (TEST_VALUE - 2):
        saved_obj = new
print("before possible crash")
saved_obj.name
print("after possible crash")