In some cases stylua removes significant whitespace around strings which are enclosed by [[ and ]].
For example
local map = {
[ [['test']] ] = 'test',
}
print(map[ [['test']] ])
After running stylua against it the spaces around [['test']] are removed...

... which leads to invalid lua code:
local map = {
[[['test']]] = 'test',
}
print(map[[['test']]])