Samaritan Pentateuch (SAM) applies the punishment only to the man (the subsequent context indicates – really - that only that man was liable to offer a sacrifice for his sin). In fact, Lange quoted SAM’s two sentences: “The Sam[aritan] reading is remarkable בקרת תהיה לו = ‘he shall be punished’, and then, in the sing. לא יומת = ‘he shall not die.’”, and after Lange glossed (bold is mine): “This gives a sense agreeing excellently with the reason assigned because she was not free, and hence the act did not legally constitute adultery which was punishable with death.”
Along these lines, NKJV Study Bible explains (bold is mine): “The concubine, a woman of low social standing and few rights, may not have the freedom to cry out when approached sexually. Therefore, she remains guiltless. Because the woman was a slave, the man escaped death but remained guilty before God. Atonement was necessary for him to receive forgiveness. ‘There shall be scourging’ may be rephrased as ‘damages must be paid’.” The woman’s owner [namely, her fiancé] probably received the [money’s] compensation, since the passage emphasizes that no money had yet been paid for her.”
Also one of them, Wordsworth, although he translated “she shall be scourged” in the main text, he was forced to admit, in the corresponding footnote: “she shall be scourged, rather, there shall be animadversion, visitation, bikoreth: Gesen(ius), pp. 136-7”]).
Really, the key-word (that a number of translators render ‘to punish’, and alike, or, even worse - as we have seen above - ‘to scourge’, is derived by the Hebrew conceptual root בקר, ‘to dig’, in the sense (also in English language!) of ‘to dig deeper into an affair’ (see also the usage of this term in Bible passages as Lev 13:36; 27:33; Psa 27:4).
Corrispondingly, the LXX has, in Lev 19:20, a term derived from the Greek verb επισκοπεω which means also (like Hebrew) ‘to inquire’.
Parkhurst commented: “The LXX have generally as a V[erb] rendered it by episkeptomai, ‘to look upon’, ‘survey’ ‘look accurately’ or ‘diligently’ […].” (A Hebrew and English Lexicon […], on בקר).
LXX (NETS): “And if one lies with a woman in a bed of semen and she is a domestic carefully guarded for a man but she by means of release had not been ransomed neither had freedom been given her, they shall get an inquiry. They shall not die, since she had not been freed, and he shall bring […].”
Accordingly, professor Giorgio Paximadi, a translator of Leviticus (for the edition of the publisher house San Paolo [Alba CN, Italy] – Nuova Versione della Bibbia dai Testi Antichi) renders: “…vi sarà un’inchiesta” [“there shall be an inquiry”], and, in the corresponding footnote he writes: “‘Inchiesta’. [Parola] derivata dal verbo […], ‘investigare’, ‘esaminare’ […]. […] il caso sarebbe meritevole di pena capitale se la donna fosse libera; l’inchiesta è dunque un atto dovuto, ma stante la condizione non libera della donna, la conseguenza non è la pena di morte.” [“‘Inquiry’. (A term) derived by the verb (…), ‘to investigate’, ‘to examinate’ (…). (…) the case would be liable to death penalty if the woman were free; the inquiry was, then, a (legal) instrument, but owing to the woman’s non-free condition, the consequence is not the death penalty.”] (Levitico, ad locum)
The same interpretation in the following Bible translations:
NLT: “If a man has sex with a slave girl whose freedom has never been purchased but who is committed to become another man’s wife, he must pay full compensation to her master. But since she is not a free woman, neither the man nor the woman will be put to death.”
Robert Alter translates: “[…] there shall be an inquiry”. Moreover, the corresponding footnote states: “A female slave, not being a free agent, would not receive the death penalty […]. After an inquiry, a monetary penalty will be set to be paid [by her master] to the man who betrothed her.”
ESV: “If a man lies sexually with a woman who is a slave, assigned to another man and not yet ransomed or given her freedom, a distinction shall be made. They shall not be put to death, because she was not free; but he shall […].”
NJB: “[…] he will be liable for a fine […].”
JPS Study Bible: “[…] there shall be an indemnity […].”
CEI: “… [l’uomo] dovrà pagare un risarcimento.” “… [(the man) will must pay a claim.”
Reaching a conclusion…
Both Hebrew (as well as Samaritan Pentateuch) and Greek texts point to the fact that an inquiry (from בקר, in Hebrew; from επισκοπεω, in Greek) was carried out, and after having ascertain the facts, namely, that she was a not-redeemed betrothed slave, his master was found guilty but without deserving death penalty. He did must perform a sacrifice to God and pay a claim to the man who betrothed her (see Alter’s translation and NKJV Study Bible).
All this, is in full harmony with the balanced God's personality, according the Scriptures.
So, I ask myself, was now the engaged man capable to pay the ‘redemption’ price, so he was able to free his fiancée?