Getting "None" Marketing channel detail when break down with marketing channel

Ok, so that pretty much proves that none of your "display" ad content is coming via a search engine, so setting your detail to "Search Engine" is the wrong option.

Now, what you do choose will be determined by what is more important...  I assume your display ads all have campaigns (likely what is driving the logic of the rule), so you can set the detail to your cid (or whatever you are using) or your tracking code value.

Or if you are more interested in the domain driving the display ad, you can choose "Referring Domain".

Personally, if I have a campaign code, I choose the first option, as that also gives me clarity to the specific campaign... and you might be thinking, "but I already have Tracking Code"... well you do, but given that tracking code only looks at campaigns and no other factors (referrer, etc) and the fact that by default your Marketing Channel has a 30 day attribution, whereas Tracking Code only has a 1 Week attribution... correlating Marketing Channels to Tracking Code is a perfect way to get strange, inaccurate, and confusing results (unless you are looking at the Marketing Channel Instance metric, since that takes attribution out of the equation and makes sure you don't get weird mis-matches....