Symptoms:
In the case when system locale was different from English (it was Russian in my case) the text with diacritic marks was distorted during export into RTF (from different code page). Printing worked fine. If locale for non-Unicode programs was set to English all works fine too. The attempts to set locale to English exclusively for Logos software (by using Microsoft's AppLocale) were failed.
Example:
Resource:
Blaising, Craig A., and Carmen S. Hardin, eds. Psalms 1–50. Ancient Christian Commentary on Scripture. Downers Grove, IL: InterVarsity Press, 2008. (LLS:ACCSREVOT07 2013-05-15T21:32:34Z ACCSREVOT07.logos4)
INTRODUCTION TO PSALMS 1–50 -> Greek Authors -> Footnote #14:
Original (=printed)
System Locale is set to Russian (Russia)

System Locale is set to English (United States)
