Some fireplace remotes are stateful, and check the original remote’s state as well.
Bond staff generally recommend taking out the batteries of the original remote once the signal is learned.
Have you tried finishing setup, saying “yes, it worked” if promoted, taken the batteries out of the original remote, and then tried to tap the Bond app button for whatever state the fireplace actually is in, first, then tapping the opposite Bond app button?
Fireplaces are probably the most difficult type of device from what I see on the forum – though I don’t personally have one. 
At least some Heat 'n Glo devices use a rolling code and somewhat frustratingly for DIYers, they have not released details for the public or Bond team to integrate.