Our hunch is that the Ai told them this was ok to do, but it broke invariants users relied on. Perhaps it was not "hackable" in the sense I think you are getting at, but it did open a very big security hole through choices and design. The critical thinking was lacking (imo).
https://github.com/anomalyco/opencode/pull/51337
The bots make mistakes all the time, even through multiple rounds of reviews. Thus I have zero faith that they will produce secure code reliably 100% of the time. More Ai does not magically fix this, they go down the wrong path and double down, or work around incorrect assumptions.
This is a good talk by a member of the Linux security team: https://www.youtube.com/watch?v=NnV_cWeoo5Q
Also worth noting that OpenCode Console was hacked days after the configuration regression and two PRs to change it back. Notable because it shows a pattern.