Digging through some of the bug details, this spawned a couple of separate bugs due to the nature of the issue.
Each bug needs to have a fix created, tested, approved, and deployed. This was more than a short-term hotfix could address, and more work than the team could balance with other items in flight. Had to be pushed back a few releases to ensure proper attention could be given. Always sucks when a fix goes out and it ends up making the issue worse, right? Want to be sure to avoid that.
In terms of "why wasn't this prioritized higher?" - The issue repro's semi-frequently, but not often enough to disable the exotic or push over other existing work. I agree that it can be annoying to die to, and I've even lost a couple of Trials rounds to it, but it's not as egregious as other bugs we've seen in the sandbox.
Now, before you link me to a clip of someone getting a 5-piece with Dunes, prioritization also considers frequency. The double chain doesn't happen every single time, but if it did, we absolutely would have pushed for a bit of a faster fix. All things considered, this would have been nice to fix faster, but we're excited to get the bug smashed as soon as we can.