It seems that at least in $group stages, the wrong indentations create issues to the parser.

A quick investigation showed that acorn returns different output depending on the indentation. We are using acorn-loose, which in their README says:

It will, to recover from missing brackets, treat whitespace as significant, which has the downside that it might mis-parse a valid but weirdly indented file. It is recommended to always try a parse with the regular acorn parser first, and only fall back to this parser when that one finds syntax errors.

We should probably do that.