Stratégia and prostitúcia in Slovak

I was surprised a few days ago when I found out that Slovak has stratégia and prostitúcia instead of štratégia and proštitúcia, which I would have expected, despite their predilection for št and šp (pronounced sht and shp) in words of Latin or Greek origin, which they probably got from German, as German also pronounces sht and shp, but only at the beginning of words. Other examples are študent, inšpirácia, inštitúcia, konštitúcia, where Czech has student, inspirace, konstituce, and instituce (no sht or shp sound).