As I posted my individual feedback as https://appsrv.cse.cuhk.edu.hk/~irg/irg/irg57/IRGN2478FeedbackOnJPlaceNames.pdf , the submitter is expected to provide more materials to evaluate the requirements and the stability of the proposed glyph. I'm afraid that the number of the paper including this character is only one.

The quoted part from 說文 (ShuowenJiezi) in post-Sung edition for "孑" is like these:
(南宋刊元修大徐本(海源閣本), 巻14下 葉6左)

(清道光19年 祁寯藻刊 小徐本, 巻28 葉13左)


The "L" like glyph in SW description is not "𠃊" (of 直) or "乚" (of "礼"), as the description says as 象形, and no self-standing entry is found in SW. In my understanding, "(了 is a figure without both arms, and) 孑 is a figure without right arm". I guess, the glyph in 慧琳一切経音義 might be the explanation influenced by 楷書 shape of "孑", and it is difficult to conclude as "㇀"-like glyph as self-standing character, meaning "left arm", by 慧琳一切経音義.

"無右臂從了象形㇀聲也㇀音厥" in 慧琳一切経音義 is slightly hard for me to understand precisely. "㇀聲也㇀音厥" looks as if this character were 形聲 composition (radical & pronunciation), but if so, why "從了象形"? In post-Sung dynasty versions of 説文, 形聲 composition is regularly described as "從A,B聲". In the 説文 quoted in 慧琳一切経音義, "従A象形B聲也" is frequent?

https://hc.jsecs.org/irg/ws2017/app/index.php?find=UK-10375 , which has 区 at the position of 𠤭 in U+25BB9 𥮹. I was questionable whether they can be dealt as the disunification example. According to Henry's comment during IRG59, from their pronunciations, they are regarded as non-cognate, should not be dealt as disunification example.