I thankfully migrated or left all Aurelia projects, but every time someone mentions it, I remember new horror stories.
Its .html temples were shipped unmodified directly to the client. Except they weren't actually html, and sometimes the browser would try to clean them up, breaking the template.
Reactivity was achieved through all kinds of weird mechanisms (eg monkey-patching arrays to watch for mutations). It would frequently resort to polling on every tick or break completely.
DI used TypeScripts experimental decorators, even long after it was clear that it would never become stable.
On the other hand, templates weren't type checked.