Corrupt Glyph/Glyph can't be used

Hey I am working on an application in which an iconfont is used.
Before the glyph “U+263C/☼/WHITE SUN WITH RAYS” has been used for a brightness icon.
Suddenly for some reason whenever I export my new font this specific icon is not available for this glyph.

So to sum it up the glyph U+263C cannot be used for any icon anymore which would mean all programmers would have to change the icon in every case (and we have a lot). So I want to avoid that and just try to make this specific slot available again… Anyone any idea what the problem might be ? :confused:

What is also interesting is that the specific icon gets identified as “WHITE SUN WITH RAYS”. Within Glyphs its just “SUN WITH RAYS” but its both on U+263C.

How are you testing your font?

It could be a font cache problem. Read this please:
http://www.glyphsapp.com/tutorials/eliminating-font-cache-problems