It seems that the character comes from 故鄉消息 by 丁明登(蓮侣), presumably published in late Ming dynasty. 故鄉消息 is quoted by 淨土晨鐘 and 衛生集 and 淨土晨鐘. Both of them give ⿹⺄𢆰:

The second character in folio b:

▲ 衛生集（清同治刊本）卷下 folio 41

(the 7th character)

▲ 淨土晨鐘（大藏新纂卍續藏經）卷5

The shape ⿹⺄𢆰 also presents 中華書局宋體字庫Plane15 (U+F8444):



A possible relationship could be ⿱⿹⺄夕一 ~ ⿹⺄彑 ~ ⿹⺄𢆰

Should we update the glyph?

Agree to update the glyph to match the new evidence.

This is and the character next to it, are arguably not transcriptions of Sanskrit, but attempts to reproduce forms of the Siddham characters "ni" and "svā" Variants of this script can be found throughout East Asia. We should consider whether to encode the complete alphabet and combinations in a separate block.

The Han script sometimes incorporates characters and symbols from other writing systems, for example 𣥬𤔞𧳤𠐂 are corrupt forms of the Tangut characters 𘜶𗵐𘏨𘔭 recorded in a Song dynasty numismatic work; U+303C3 𰏃 is a corrupt form of a Khitan character; U+2CF01 𬼁 is derived from the dram sign ʒ (U+0292); U+2CF04 𬼄 is derived from the ounce sign ℥ (U+2125); and WS2021 UTC-03225 is derived from the pound sign ℔ (U+2114). In the sources for UK-20570 etc. corrupt forms of certain syllables of the Siddham script which are used in mantras have been treated as Han characters, so it is appropriate to encode them as Han ideographs. Note that the Siddham script is already encoded since Unicode 7.0, so encoding these particular Han-ified Siddham syllables does not affect the use of Unicode Siddham.

It might be premature to change the shape. ⿱⿹⺄夕一 and ⿹⺄𢆰 possibly represent different Sanskrit syllables. The original evidence only explains ⿱⿹⺄夕一 as 尼. However, 尼 is used to write both dental "ni" (e.g 釋迦牟尼 śākyamuni) and retroflex "ṇi" (摩尼 maṇi). If these are attempts to represent some Brahmic script (梵書), it's possible that the difference in shape reflects the different sounds. The evidence for ⿹⺄𢆰 shows it the context of a dhāraṇī that is clearly "ṇi" in "maṇi". It would be safer to see ⿱⿹⺄夕一 in context to determine whether they are the same or different.

Via Sven Osterkamp (@schrift_sprache) on twitter, these are the nine characters in 《字孳補》 (the source used for the glyph forms in the UK submission), which together form the Mantra of Ratnasikhine Tathagata (寶髻如來護生咒), i.e. 唵縛嚩悉波羅摩尼莎訶 which corresponds to "oṁ va svara maṇi svāhā" in Sanskrit. The 7th character corresponds to Sanskrit ṇi, which matches the evidence given by Huang Junliang in #13137, thus I think both glyph forms represent the same Sanskrit transcription character, so it should be OK to change the glyph form for UK-20570 based on the new evidence.

Via Edward W. (@edwardW2) on twitter, this is an example of the Mantra of Ratnasikhine Tathagata (寶髻如來護生咒) from 《通天曉》(1841 ed.), here noted as corresponding to "唵縛嚩悉波羅摩尼莎訶" (i,e, "oṁ va svara maṇi svāhā"). The glyph form for the 7th character matches the form shown in the evidence from Huang Junliang (also the glyph forms for the 1st, 3rd, and 9th characters match the correct forms suggested by evidence from Huang Junliang).

Agree with Andrew's comment in #14761

▲ 淨土晨鐘（世界書局，1937）pp. 66

Based on the additional evidence provided by Huang Junliang I agreed to change the glyph to ⿹⺄𢆰, but during the meeting this week I got confused, and agreed to no glyph change. This was a mistake, and the glyph should be changed to ⿹⺄𢆰.

⿹⺄𢆰

FS=1