Open Sans tilde glyph renders like minus or ndash at some sizes

Tested on Windows Chrome and Edge browsers.

At 13px, 10px, 9px and 7px the tilde (~) is rendered completely flat, like a minus or an ndash.

This can be misleading, as "~50%" (approximately fifty percent) has a very different meaning to "−50%" (negative fifty percent). Glyph hinting/instructions should be improved.