Assume that you add more than 22 entries to the IP Address list on the property page for TN3270 LU and LU Pool in SNA Manager. After you save the changes and reopen the property page, only the first 22 entries are displayed. The remaining entries are removed, and no error message is displayed.
Cumulative update information
The fix that resolves this problem is included in Cumulative Update 2 for Host Integration Server 2013.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.