The character ⿱暗灬 seems unlikely in the context, and is probably a mistake for some other character. Google books finds "只為一人長期翠裙羅费似烟" in 《天津圖書館孤本祕籍叢書: 史部》 but does not show me the actual text, and "费" does not seem plausible either. However, it does indicate that there is a source for the text shown in the evidence, so I think we need to find other examples of the text in order to confirm what the actual character is. Therefore suggest to postpone pending addditional evidence.

▲ 李昉 等：《文苑英華》，四庫全書本，卷七百三十四

Compared with the following picture, it is the variant of 黯.

▲ 駱賓王：《駱丞集》，金華叢書，卷一

The author of this classical prose is 駱賓王.

U+9EEF 黯

啽囈集 confirms that ⿱暗灬 in the first evidence is indeed a variant of 黯:



This and the additional evidence provided by Eiso Chan indicates that it is OK to keep UK-20132 in the M-set.

The glyph should be modified to make the 日 component taller.