Eh the way I see it, an implementation either passes the canonical Lua test suite(s) or it doesn't.
This may be a place where “technically correct is the best correct” doesn’t hold, at least in terms of community psychology.
I have a pretty small data set (5 people) and three of them are guile users.
Scheme is however willfully underspecified, whereas most other languages lack specifications of even a proper base language (except for code). Implementing scheme is pretty easy apart from continuations and macro hygiene, but those parts are very well specified somat least you know what you are aiming for.