LGPL does not bind the author(s) of the software in this way. And since there was a CLA the other authors authorized the main dev to change the license.
Thank you! This is the piece of information I was missing. I kept wondering as I read the article whether that was a LGPL license breach. Thanks for clarifying
As the owner of the intellectual property you're the one licensing to others. License is a kind of contract. You're not under any license yourself, it's yours.
If you accepted PRs without a contributor agreement transferring the ownership, you might be infringing on their IP (licensed to you and others).