I am running a test of Spark and Openfire for my company, and we have noticed issues with history as well. Yesterday I had a long discussion with one of my coworkers about a problem we are working on. Today, he went to refer back to his history and found that almost all of the messages were not saved in his history. Luckily it was in mine, so I emailed him a copy of my history. I am running Spark 2.5.1, he is running 2.5.2beta1.
Aside from the issues with the limited UI of the history, it is important for us to be able to reliably refer back to old conversations in the history.