Learn Russian: Обе стороны правы, хотя этот случай странный. - Both sides are right, although this case is strange.

The word for "both" has two forms in the Nominative case: оба for masculine and neuter nouns, and обе for feminine nouns. Since сторона (side) is feminine, we use обе. After оба or обе, the noun takes the Genitive singular form, which is стороны.

Is the stress on стороны any different here?

Yes, it is! The normal Genitive singular of сторона is стороны with the stress on the last syllable. However, as an exception after the numbers 2, 3, 4, and the word обе, the stress shifts to the first syllable: обе стороны.

Why is правы used here instead of the full adjective правые?

правы is the short-form adjective. In Russian, to say that someone "is right" or "is wrong", you almost exclusively use the short forms (прав, права, право, правы). We use the plural правы because the subject, обе стороны (both sides), acts as a plural group.

Why use the long-form adjective странный at the end instead of a short form like странен?

While short forms are great for temporary states (like правы), long forms are extremely common as predicates in everyday Russian to describe a general characteristic. Saying этот случай странный sounds perfectly natural and less formal than the short form странен.