Comment by varispeed
If Pegasus can break the iOS security model, there’s no reason to think it politely respects Lockdown Mode. It’s basically an admission the model failed, with features turned off so users feel like they’re doing something about it.
Lockdown mode works by reducing the surface area of possible exploits. I don't think there's any failures here. Apple puts a lot of effort into resolving web-based exploits, but they can also prevent entire classes of exploits by just blocking you from opening any URL in iMessage. It's safer, but most users wouldn't accept that trade-off.