ShowMojo's Listing Merge feature may exhibit unintended behaviors when used with listings that are generated from active Listing Import Sources. ("Active" as in: enabled on the Import Settings page.) 

Do Not Merge Two Imported Listings from the Same Active Import Source

Merging two listings from the same source system (Rent Manager, for example) will result in a successful merge -- initially. 

However, when the automated importer for that system runs again (typically every four hours), ShowMojo will look for listings in the third-party system that do not exist on your account. Since the "source" listing that had been removed during the merge no longer exists on your account, ShowMojo will create a new one in its place.

The end result is that ShowMojo will create a new version of the "source" listing, giving the appearance that the merge action somehow failed or reverted.

Do Not Merge Two Imported Listings from two Different Active Import Sources

In theory this action will work. ShowMojo will maintain the single listing and not create a new copy as the automated imports run.

However, when ShowMojo matches the merged listing to each of the independent source systems, ShowMojo will sync the data and photos from each specific system. Unless the two import systems contain the exact same information, the listing will flip from the details of the one system to the other system after each import.