Proposal 69

Let's say I enchant a Mesmer with Echo. Then, while under the effects of Echo, I enchant the Mesmer with Echo again. The first Echo ends, but then due to the second Echo, I can enchant the Mesmer with Echo again. And then I enchant it with Echo again. And so on, so forth...

Probably not a loophole, but more of an oddity if anything. Although I'm not sure if this could somehow be exploited at a later time.