bug#25148:

[Eli Zaretskii]

> From: skrechy@gmail.com
> Date: Wed, 14 Dec 2016 19:00:51 +0200
> 
> Ahaaaa!
> Yes, I have non-ASCII characters! The characters that are causing this
> are:
> 
>              position: 2465 of 4273 (58%), column: 30
>             character: ⓐ (displayed as ⓐ) (codepoint 9424, #o22320, #x24d0)
>     preferred charset: unicode (Unicode (ISO10646))
> code point in charset: 0x24D0
>                script: symbol
>                syntax: w      which means: word
>              category: .:Base, L:Left-to-right (strong), h:Korean, 
> j:Japanese, l:Latin
>              to input: type "C-x 8 RET 24d0" or "C-x 8 RET CIRCLED LATIN 
> SMALL LETTER A"
>           buffer code: #xE2 #x93 #x90
>             file code: #xE2 #x93 #x90 (encoded by coding system utf-8-unix)
>               display: by this font (glyph code)
>     uniscribe:-outline-Malgun 
> Gothic-normal-normal-normal-sans-13-*-*-*-p-*-ksc5601.1987-0 (#xDB)

Then I think installing the Symbola font will make the problem go away
for you even without setting inhibit-compacting-font-caches non-nil.