Closing as won't fix. Due to the way the event engine works, it is necessary that created/spawned instances are not fully created until the end of the next top-level event (in this case, the entire "trigger once" branch must finish before the instance is fully created). Otherwise it can only be accessed in the very same event it was created in. Workaround: use separate top-level events, firstly creating any objects you need, then manipulating them.
BTW "pick spawnee instance 1" makes no sense as a sub-event to a "spawn" action. The "spawn" action picks just the created instance. Everything is zero-based, so picking instance 1 picks the second instance; no such instance exists.