Okay, I've officially decided, it is indeed toxic yuri.
Zapple is completely oblivious to the fact that Carr hates her guts, which is why she keeps showing up, and just thinks Carr is trying to hide the fact that she likes her and/or playing hard to get.
The reason Carr is so pissed, is because 1: she's subconsciously jealous of Zapple's joy and whimsy, 2: Zapple constantly interrupts her and her work and overall just gets on her nerves, 3: Zapple purposefully acts like a nuisance to Carr (it's her love language) and makes Carr's life actively worse whether it be through destroying things, belittling her, or just wasting her time.
Which is funnier, because I headcanon Carr as Asexual, and a moot of mine said that Carr may actually be AroAce.
Bapple has tried to intervene, but Zapple is in a whole nother level of denial so its not worked very well.
Ironically, Car and Zaps get on perfectly fine because they compliment each others silliness.
Car has asked Zapple to relay some messages from him to Carr, which pisses Carr off even more.
TL;DR: They're in a constant "Are you two girlfriends?" "NO." "Yes!" situation