I found the cause of this bug !
It's all because of Gantry. Look:
1. install J! 1.7.3
2. install MC 2.2 - fonts is ok.
3. then I may install any components, templates (wo gantry), etc. - everything will be ok!
But if I install any template bundled with Gantry, or Gantry 3.2.13 alone, we have my first screenshot again!
You were right. "it must be something related to some 3rd party extension you have installed". Tis extension is Gantry framework. :shock: