Yes I'm aware of the banner. However, the 119, 234 chain is not affected by that. Unless there is a banner on the investigate action on 119 Gold. Hopefully a developer can chime in here.
You could fight the beetle over and over. If you do so and need to take card 234 (which won't be available anymore), you'll have to return all cards from the Past.
Card 234's back allows you something that wouldn't be available anymore if the card was banished after killing the bug.