Bubble and Flower have been against each other in BFDI, where Flower's rude behavior forced Bubble to stand up to her on a couple of occasions, most notable in BFDI 25.
In BFB, however, even though they were on the same team before the split, they didn't seem as hateful to each other as before, with their conflict slowly cooling down, until finally ending in "Chapter Complete"
Episodes suggesting a friendship
In "Getting Teardrop to Talk", Bubble tried to talk Lightning out of zapping Flower.
In "What Do You Think of Roleplay?", Bubble forgives Flower for "being so mean and annoying and selfish and oblivious all the time", which refers to her past actions in the first season, to prevent her from being eliminated. Flower looks at her with a slightly offended expression.
Between "Fashion For Your Face!" and "B.F.B = Back From Beginning", Bubble wears one of Flower's sweaters while being in the BRB and clearly likes wearing them, although this was mostly because wearing it prevented her from popping while in the BRB.
In "SOS (Save Our Show)", when the show's quality is getting worse due to the lack of a budget, Bubble urges Flower to give her $50,000 to the show, saying: "Please, Flower! Don't let our competition end like this!" Bubble, along with everyone else, cheers when Flower and Gelatin save the show.
In "Chapter Complete", Bubble happily accepts Flower's request to eat the Grand Cake with her and Ruby. This episode brings a final end to their conflict, and the two become friends. At the end, Bubble and Flower (along with Ruby, Spongy and Lollipop) sit close together as they listen to Gelatin reading his comic.
In "Getting Teardrop to Talk", when Flower says "Observe me please!", Bubble anxiously says "I'm a bember!".
In "Get to the Top in 500 Steps", when Flower volunteers to run for her team, Bubble just says okay.
In "What Do You Think of Roleplay?", seeing Snowball pop Bubble made it clear to Flower and Ruby that neither of them were the impostor on their team.
In "Return of the Rocket Ship", Flower points out how the alliance is only Bubble and Ruby. When Ice Cube decides to join iance, Flower says she can't just do that but Bubble hushes Flower and tells her to let Ice Cube believe what she wants. When Flower accidentally falls on Team Ice Cube! and pops Bubble, she says it's no big deal since this isn't even the first time she's killed Bubble and brings up the finale as an example.
In "Take the Tower", Bubble tries to impersonate Flower in order to infiltrate the other team's tower.
Episodes suggesting a conflict
In "Take the Plunge: Part 2", Bubble defends Teardrop when Flower calls her stupid. Flower demands that Snowball beat Bubble up, but he refuses. However, Blocky agrees that he will beat up Bubble, much to Flower's delight.
In "Sweet Tooth", Flower steps on Bubble's lent cake out of anger before judging it, then gives it a low score for looking terrible.
In "Hurtful!", Flower pushes Bubble into the metal furnace. During the challenge, when Flower demands that Bubble help her over the rock wall, Bubble denies her request, saying that Flower will have to do it herself. Flower tells Bubble that Bubble isn't nice. Bubble continues to refuse to help Flower over the wall, so Flower threatens to and then actually pops Bubble. Once Bubble catches back up with Flower, she helps her over the wall, but she's "only doing this because" Flower will kill her if she doesn't. Bubble tosses Flower up to a spot with a boxing glove trap, likely a coincidence. At the final leg of the contest, Leafy accuses Bubble of preferring a friendship with Flower, which Flower claims is true. Bubble denies this, but Flower notes that Bubble helped Flower over the rock wall, which shocks Leafy. Bubble tries to explain that it was only because Flower threatened her, but Leafy cuts her off, stating that their friendship is over, to which Flower exclaims her friendship with Bubble has just begun. With a smile, Flower demands that Bubble throw her out of the volcano, but Bubble turns around and drops Flower into the lava.
In "Insectophobe's Nightmare 2", Flower demands that Bubble apologize for not handing over her immunity, but not before pulling a "you know exactly the reason" thing. Bubble angrily refuses to apologize for this. Leafy apologizes in her place, which Flower accepts.
In "Return of the Hang Glider", Bubble seems perturbed by the sight of Flower biting a chunk out of Announcer. Flower has held a grudge because Firey, Leafy, and Bubble had all killed her, so she doesn't want any of them to win. When Flower is recovered and asks everyone why they aren't celebrating, Bubble confronts her, saying "Flower, I'm tired of this... I mean I'm tired of your self-centeredness. I'm tired of the way you act around us. You know what that means? I'm tired of you!". She tells Flower that her unpopularity is her own fault. Obviously, Flower doesn't take well to this and goes on a rampage destroying recovery centers, starting with the BRC. Once she's destroyed all the recovery centers, Flower killed Bubble, which for the moment seemed permanent.