2016 AM 2B - yield widening - country beta not used?

Why isn’t the country beta applied to calculate the duration? I though it the duration would be 8 * 0.5 country beta = 4 instead of 8.

The country beta was applied in the first question to calc the weighted average duration.

https://www.analystforum.com/forums/cfa-forums/cfa-level-iii-forum/91358733

Thanks, there are so many nuances that are easily missed!