Here is а question on this matter.
Appearing ё for e. Повернýть -> повёрнутый, повернута (short form), ( and in verbs like развернýть), that I suppose stressed повéрнута. In the dictionary it presents as a rule in verbs like these, but my problem is why appears this ё not being in its stem nor in past; just obviously in present 2nd person sing. I have no explanation for it, save of course: Roma locuta est, causa finita . Thank you.