Is spontaneous evolution an oxymoron?
No. Why would you think it is?
Actually, in a way it is. Since it’s more correct to say spontaneous mutation. It’s not like there’s some master plan and the next generation of a critter just spontaniously takes the next step.
It may be a malapropism. Evolution is an ongoing process, the adjective spontaneous doesn’t seem applicable to me. Some COMPONENTS or ASPECTS of evolution may be spontaneous.
Question–what exactly do you mean by spontaneous evolution?