The master key in SLIP-0039 wallets are not derived from a BIP-0039 seed, so there is no actual way to convert a set of SLIP-0039 shares into a BIP-0039 mnemonic (would need to break a hash for that).
This is all fine, but it needs to be documented better that if someone actually wants to use the SLIP-0039 algorithms to share a BIP-0039 seed instead of the master key, it is not conforming to the specification. Also, it is somewhat unclear how SLIP-0039 would extend to support multiple curves, like it is described in SLIP-0010
The master key in SLIP-0039 wallets are not derived from a BIP-0039 seed, so there is no actual way to convert a set of SLIP-0039 shares into a BIP-0039 mnemonic (would need to break a hash for that).
https://github.com/iancoleman/slip39/issues/1#issuecomment-563213494
This is all fine, but it needs to be documented better that if someone actually wants to use the SLIP-0039 algorithms to share a BIP-0039 seed instead of the master key, it is not conforming to the specification. Also, it is somewhat unclear how SLIP-0039 would extend to support multiple curves, like it is described in SLIP-0010