Here in the original manuscript, Oliver Cowdery initially wrote the singular affliction. He then redipped his quill in the ink and started to write the following text inline with somewhat heavier ink flow: “& this because of the great wickedness”. The ink level for Oliver’s correction of affliction to afflictions shows the same level of increased ink flow; quite possibly after redipping his quill, Oliver inserted inline the plural s for afflictions. Most likely, Joseph Smith dictated the plural afflictions.
The text has eight other instances of “all manner of afflictions” but none of the singular “all manner of affliction”. Nearby, in Alma 60:3, we have this example: “and all manner of afflictions of every kind”. In modern English, we expect the singular, and this may have been the source for Oliver Cowdery initially writing the singular in 𝓞. Here the corrected reading in 𝓞 appears to be fully intended, so the critical text will maintain it. As noted in the discussion under 1 Nephi 16:35, the critical text will in each case of affliction(s) look to the earliest textual evidence. Here in Alma 60:17, that evidence supports the plural.
Summary: Maintain the plural afflictions in all examples of “all manner of affliction(s)”, including Alma 60:17.