How could Yoseph have been named Yoseph? A theophoric* problem.

Shemot 6:2-3

ב וַיְדַבֵּר אֱלֹהִים, אֶל-מֹשֶׁה; וַיֹּאמֶר אֵלָיו, אֲנִי יְהוָה.	2 And God spoke unto Moses, and said unto him: 'I am the LORD;
ג וָאֵרָא, אֶל-אַבְרָהָם אֶל-יִצְחָק וְאֶל-יַעֲקֹב--בְּאֵל שַׁדָּי; וּשְׁמִי יְהוָה, לֹא נוֹדַעְתִּי לָהֶם.	3 and I appeared unto Abraham, unto Isaac, and unto Jacob, as God Almighty, but by My name YHWH I made Me not known to them.

Aren't the names יוסף (Yoseph) and יוכבד (Yocheved) theophoric, that is, aren't they shortened forms of יהוסף (Yehoseph) and יהוכבד (Yehocheved)? Although I am a little more hesitant to say that with certainty about the second name, I think its fairly certain that Yoseph is Yehoseph.

This phenomenon is not that dissimilar to how יהונתן (Yehonatan) and יהוחנן (Yehochanan) become יונתן (Yonatan) and יוחנן (Yochanan) respectively, especially in pronunciation--a later example is from European Jewish culture, in which יהודה (Yehuda) became יודה (Yuda) or even יהודא?

If "by My name YHWH I made Me not known to them," then how were Yoseph, if not Yocheved, named with the י-ו element in their name?

*Theophoric names are personal names which contain elements of a deity's name within it. There are many Hebrew and Arabic names with theophoric elements. An old post about these names.