Rashi to Bamidbor 26 (5) commenting on the words מִשְׁפַּחַת הַחֲנֹכִי says:
the family of the Hanochites: Heb. מִשְׁפַּחַת הַחֲנֹכִי. Since the nations were denigrating them and saying, “How can they trace their lineage by their tribes? Do they think that the Egyptians did not exploit their mothers? If they mastered their bodies, all the more so [did they exercise authority over] their wives. Therefore, the Holy One, blessed is he, appended His Name to them, the [letter] ‘hey’ to one side and the ‘yud’ to the other side, as if to say, ”I bear witness for them, that these are the sons of their fathers.”
We find the same construction with the families of the Levi'im in for example 26 (57)
וְאֵלֶּה פְקוּדֵי הַלֵּוִי לְמִשְׁפְּחֹתָם לְגֵרְשׁוֹן מִשְׁפַּחַת הַגֵּרְשֻׁנִּי לִקְהָת מִשְׁפַּחַת הַקְּהָתִי לִמְרָרִי מִשְׁפַּחַת הַמְּרָרִי
But the Levi'im were not enslaved so why was it necessary for Hashem to append his name to them?
A possible answer might be that the nations who were denigrating Klal Yisroel did not know that the Levi'im were not enslaved and had another way of explaining how it was that Moshe and Aharon were able to enter the palace of Paroh. But there must be a better answer.