Cannot create more than five items in the Transformation List

An error has occurred.
DotNetNuke.Services.Exceptions.PageLoadException:
An error has occurred because a control with id 'dnn$ctr943$FriendlierUrlProviderConfig$ctlFriendlierSettings$ctl09$DefaultBehaviour$FriendlierUrlStrategy$ctl13$ExpressionFilter$ExpressionFilterInfo$ctl03$TransformList$ctl04' could not be located or a different control is assigned to the same ID after postback. If the ID is not assigned, explicitly set the ID property of controls that raise postback events to avoid this error. ---> System.Web.HttpException: An error has occurred because a control with id 'dnn$ctr943$FriendlierUrlProviderConfig$ctlFriendlierSettings$ctl09$DefaultBehaviour$FriendlierUrlStrategy$ctl13$ExpressionFilter$ExpressionFilterInfo$ctl03$TransformList$ctl04' could not be located or a different control is assigned to the same ID after postback.
If the ID is not assigned, explicitly set the ID property of controls that raise postback events to avoid this error.
at System.Web.UI.Page.ProcessPostData(NameValueCollection postData, Boolean fBeforeLoad) at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)
--- End of inner exception stack trace ---