If the FBI themselves admits he was an Undercover Employee and he then confirms it, I see no room for doubt
in May of 2016 he was an Undercover Employee of the FBI and in October he was a dangerous spy threatening National Security, and he has still not been arrested or charged.
The FBI obtained the recordings after Sporyshev attempted to recruit an FBI undercover employee (“UCE-1”), who was posing as an analyst from a New York-based energy company.
Neither of those two things have happened, so you'll excuse my skepticism.
Page ran a energy consulting company in New York and was in contact with the Russian targets of the investigation, so it's feasible the FBI asked him to let one of their agents pose as an analyst at his company to gather evidence.
Doesn't make Page himself an undercover FBI employee , it just makes him a cooperating witness to their investigation.