We don't use the entity's toString, at least not directly. In fact I am surprised you see calls to an entity's toString here because that would mean something is causing the entity itself to be stored into the cache as "disassembled state" which is generally not a good sign. In fact, here is the StandardCacheEntryImpl#toString impl:

	@Override
	public String toString() {
		return "CacheEntry(" + subclass + ')' + ArrayHelper.toString( disassembledState );
	}

disassembledState should hold the reference-safe state of the thing being cached. For an entity that means a tuple array of its "simple" state. Entities references are disassembled to their ids.

Gail Badner does this sound familiar? I know we have had problems previously with entities being pushed into the cache entries before.

Carsten Hammer would be good to have a pared-down test demonstrating this.