It is definitely a font issue. I copy-pasted the string that @Ciencia Al Poder said contained a box into Emacs and used and describe-char to find the code point and font being used to show the character.
position: 1 of 10 (0%), column: 0
character: မ (displayed as မ) (codepoint 4121, #o10031, #x1019)
charset: unicode-bmp (Unicode Basic Multilingual Plane (U+0000..U+FFFF))
code point in charset: 0x1019
script: burmese
syntax: w which means: word
category: .:Base, L:Left-to-right (strong)
to input: type "C-x 8 RET 1019" or "C-x 8 RET MYANMAR LETTER MA"
buffer code: #xE1 #x80 #x99
file code: #xE1 #x80 #x99 (encoded by coding system utf-8)
display: composed to form "မြ" (see below)
Composed with the following character(s) "ြ" using this font:
ftcrhb:-SIL -Padauk Book-normal-normal-normal-*-13-*-*-*-*-0-iso10646-1
by these glyphs:
[0 1 4121 237 2 0 10 12 6 [0 0 10]]
[0 1 4156 172 7 0 8 6 0 [-7 0 0]]
Character code properties: customize what to show
name: MYANMAR LETTER MA
general-category: Lo (Letter, Other)
decomposition: (4121) ('မ')
Padauk Book is a font for Myanmar text from SIL International. In fact, the same font is used to show that whole word, so I'm wondering if Ciencia's problem is because his browser or OS is not displaying composed characters correctly.
@Wladek92: I think installing Padauk Book will let you display the characters correctly.