The format through language server is not the same as refmt

I'm using https://github.com/prabirshrestha/vim-lsp/wiki/Servers-OCaml---Reason to do the language server binding but when I call `:LspDocumentFormat` on a file, it messes it up quite hard. It starts indenting a lot of the lines. Is it possible it's pasting it as if the user typed it and therefore getting extra indents from vim?