inspector opened on a morph break serialization of entire world

[rksm]

Error saving world: Error: Error snapshotting morph: Cannot recreate morph from snapshot!
TypeError: Illegal constructor
    at ClassHelper_restoreIfClassInstance_ (https://lively-next.org/lively.serializer2/class-helper.js:94:56)
    at ClassPlugin_deserializeObject_ (https://lively-next.org/lively.serializer2/plugins.js:96:39)
    at ObjectPool_plugin_deserializeObject_ (https://lively-next.org/lively.serializer2/object-pool.js:325:71)
    at ObjectRef_recreateObjFromSnapshot_ (https://lively-next.org/lively.serializer2/object-pool.js:528:29)
    at Function.ObjectRef_fromSnapshot_ (https://lively-next.org/lively.serializer2/object-pool.js:592:47)
    at ObjectPool_readSnapshot_ (https://lively-next.org/lively.serializer2/object-pool.js:232:45)
    at ObjectPool_resolveFromSnapshotAndId_ (https://lively-next.org/lively.serializer2/object-pool.js:245:20)
    at Window.deserialize (https://lively-next.org/lively.serializer2/index.js:50:20)
    at step2 (https://lively-next.org/lively.serializer2/index.js:60:42)
    at <anonymous>
    at Window.createMorphSnapshot (https://lively-next.org/lively.morphic/serialization.js:114:15)
    at <anonymous>