Unicode specifies a "character", which is somewhat an abstract entity and is different from "glyph", which is a visual representation of the character. One character can be mapped to different glyphs. Usually glyphs are determined by fontset. In your case I assume glyphs of the snowman character in the fontset for the text entry and in the fontset for the text display are different.

It is a common experience for East Asians; the same CJK kanji character sometimes has different glyphs for Chinese and Japanese. It is still quite a hassle to fix all fontset to show them right (I gave up.)