I think it might be because the metric you are using, Entries is basically a calculated metric that sometimes shows some funny information when used in conjunction with segments... someone else recently was also trying to use Entries with Marketing Channels and was getting strange results.
Also keep in mind that a visit may have multiple channels... Entries is a calculation trying to find only the first value of a dimension within a visit... So by trying to use Entries, you are potentially losing a lot of cross channel attribution.
Example:
Visit:
- User is on Social Media and clicks on a post
- Page A
- Marketing Channel = "organic social"
- Marketing Channel Instance is triggered
- Page B
- Marketing Channel retains value "organic social"
- Marketing Channel Instance is not triggered
- User then wants more info, and does a Google Search
- Page C
- Marketing Channel = "organic search"
- Marketing Channel Instance is triggered
- User then gets a marketing email, and clicks on the CTA
- Page D
- Marketing Channel = "marketing email"
- Marketing Channel Instance is triggered
One visit, three channels... So if your segment was looking for "marketing email", the "Entries" value would still be "organic social" as that was the initial value set for the entry into the site.
So interestingly, "Last Touch Channel" and "Last Touch Channel Detail" are essentially duplications of "Marketing Channel" and "Marketing Channel Detail", but don't have the associated "instance", but you can use the "Marketing Channel Instances" metric.
If you are trying to see the pages that were opened directly via the specific campaigns, then you need to look at the channel instance.
