Slot synonyms in slot files

Continuing the discussion from Rhasspy 2.5 Pre-Release:

I’m running Rhasspy 2.5 (latest master as of yesterday) with snips-nlu. Something is wrong with either the way I write the slot files or the way the Snips dataset is generated.

This is my slot file (the part after “:” is what I’d like to have in the parsed intent, because I need exact strings; see below):

dynamic:Dynamic
((aggiunte|aggiunti) di recente):(Aggiunte di recente)

This is dataset.yaml generated by Rhasspy for snips-nlu:

type: entity
name: "playlist"
values:
  - "(aggiunte|aggiunti) di recente"
  - "dynamic"

I’ve tried in various ways but there is always something wrong in how the YAML is generated. What I’d like to do is leveraging Snips entity synonyms. For example, my ASR can’t clearly distinguish between “aggiunte” and “aggiunti”, but the result must be “Aggiunte”, so I wanted to create a synonym like this:

type: entity
name: "playlist"
values:
  - ["Aggiunte di recente", "aggiunti di recente"]
  - "Dynamic"

As an added value, this would allow me to translate entity values into usable values for automations (I need Rhasspy to output specific text, regardless of what the ASR recognizes, that’s why I wanted to use synonyms; those were playlist names: they must match exactly otherwise Kodi won’t find them).

I tried tapping into the code but that’s out my league – syntax parsing, jsgf code, etc. and I’m not really an expert on that stuff.

Am I misusing this feature or did I find a bug?
Thanks!