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Ame's time travel lore was originally supposed to be a cheap way for her to try out different "personalities" when streaming, while still getting a feel for the light-LARPing they have to do in hololive. If something didn't work out, she could just say it was an Ame from a different timeline, scrub it, and pretend it never happened. This was largely canned as the Myth girls quickly realized no one actually gave a shit about their lore or roleplaying, as most of JP and ID ignored theirs to begin with.
You still see this occasionally when she acts a little more unhinged when using the walfie model.