Normally any voiced velar spirants ʒ that developed from g eventually vanished, but when it appeared between two e’s it became the semi-vowel y: eʒe [eɣe] > eye [eje]. This combination ultimately became ie. This phonetic development was mentioned in both the Outline of Phonetic Development (OP1) from the 1940s and the Outline of Phonology (OP2) from the 1950s, but the details differed:

Between vowels g > ʒ > y before ē̆ (ei), with the later development as original y (OP1: PE19/32).

After ē̆, ei, ī̆ a development g > ʒ > [ı̯] occurs before a following vowel. But this only produces results of importance in ē̆gē̆ > eı̯e > i(ı̯)e, as tege “line, road” > tie (OP2: PE19/70).

It seems in the 1930s, this sound change was triggered by following e or ei, but in the 1950s, this change was triggered by a preceding e, ei or i. In practice, all the actual examples show both a preceding and following e:

• ✶tegē [> teʒē > teyē] > Q./ᴹQ. tie “line” (PE19/71; Ety/TEƷ).
• ᴹ√WEG > ᴹ✶weʒē [> weyē] > ᴹQ. vie “manhood, vigour” (Ety/WEG).

Furthermore, examples involving vowels other than e seem not to demonstrate this sound change:

• ✶wegō(n) > Q./ᴹQ. veo “living creature; man” and not **vio (PE17/189; Ety/WEG).
• ᴹ√LUG > ᴹQ. lue “it is heavy, sad” and not **luye (PE22/102).

There is a deleted note in OP2 that indicates a similar change of ʒ to w might have occurred between two o’s as well:

Between vowels and ē̆, ei a development g > ʒ > y often occurs; less frequently a development g > ʒ > w before ō̆, ou (OP2: PE19/71 note #15).

One example from The Etymologies of the 1930s seems to demonstrate oʒo > owo > uo:

• ᴹ✶Khō-gorē > ᴹQ. Huore “heart-vigour, courage” (Ety/KHŌ-N).

In later conceptual periods the name Huor was taken from an Atani language, not Elvish (PM/348, 364 note #49), so the above derivation was no longer relevant. The sound change oʒo > owo seems to have been abandoned, though given the lack of examples it is hard to say this for sure.

Conceptual Development: Lack of examples makes it hard to tell if this sound change applied to the Early Qenya of the 1910s and 1920s.