Do you think v1 and v2 knew each other before hell? And if so what do you think their relationship was like?
I doubt they actually met because V2 prototype wasn't a thing while V1 was still relevant and being tested. Once the war was over and the money invested in the first prototype became a problem, the company just stopped spending much time in V1, keeping it dormant, deactivated while simultaneously used to prepare their next project, V2. Surely maaaany things were taken from the first V model and adapted to the new one.
There was probably a lot of pressure set upon the company's engineers and robotic specialists to take as much advantage from V1 for V2's design. We cannot afford new, innovate ideas, just copy what we have and program it differently. Go for a cheaper, less warfare oriented technology, people need protection, not a weapon. Cannot sell this thing otherwise.
Considering V2's meant to accomplish a different function, it was programmed and tested several times. Since it's function is to protect, a good machine needs a flawless, unquestionable, integration of Asimov's laws, a flawless execution and a flawless calculation of priorities. Variables must always aim to what's best for a person's sake. V2 was surely learning a lot, especially morality, creativity at decision making, among other things such as fixing one or two things in their body. And well, people talked, commented about V1 and how V2 was designed around it. Being meant to serve people made it a good listener. It loved to listen, to learn, to surpass the expectations.
Comments such as "V2 performs identically to V1 in combat but doesn't know how to exploit it's durability" (of course it doesn't know, V2 fights like V1) may have been a common critique to hear for the second prototype. The machine probably never had the chance to see their predecessor, however it knew it had to prove it's worth to be considered good enough to salvage the company.
Oh, how much they loved people when V2 achieved little things by itself, by utilizing its creativity and highly adaptive program. The nice comments were nice, but it always knew that, deep down, people were still comparing it to V1. And V2 never understood why V1 was such a great comparison point besides similarities in their designs.
When they finally met, it turned out V2 was better at so many things except one. A flaw that didn't come from themself, but from their creators. Because they adapted all possible aspects from V1 to V2, except one.
Something V2 would never be able to change because it wasn't it's own incapability but a limitation by design. And that's just so unfair.
And to apply salt to the injury, they're retrocompatible.
Wouldn't that fill you with resentment?