The glyph is clear, but when you see the structure description, doesn't it apparently suggest that the character should look ⿺毛束 = 𣭴 U+23B74?

The analysis does suggest a shape of ⿺毛束. The character means "fast", hence the semantic 速. Other evidence from (Tự điển chữ Nôm trích dẫn, p. 754) shows a unifiable variant composed of 毛速 and the analysis says that the semantic, "Ý" is 速 and the phonetic "Âm" is 毛. I will try to ask the author to clarify this, but the evidence below does show that 毛速 is used.

Radical 82.0 (毛) is much more intuitive for this ideograph.

PnP section 2.2.1 d. (5) c): "If the technically correct (aka semantic) radical for an ideograph hampers its discoverability, or is region-dependent, the primary radical shall be assigned as though made by an ideograph expert who is neither a specialist in the history of the Han script nor familiar with ideograph etymology. The technically correct radical can be assigned as a second radical."

Therefore use Radical 82.0 (毛) as the primary radical for this character, and add 162.0 (辵) as a second radical if considered necessary.

According to Prof Hồng, the compiler of the dictionary, both forms are in use and the analysis is a short way to indicate that 速 can be abbreviated to 束.