Yeah, I found that interesting. I generally don't attribute to malice what can be attributed to incompetence, and I imagine either (or both) of these is likely:

1. The 'evasive' language made everything feel implied, that when pressed to outright admit his intentions he falls back. He was evasive, evasive, evasive, pressed, fell back. Still he did not clarify he was selling Apollo, only that 'go quiet' meant 'pay me off and Apollo stops making calls'. It's possible Spez did not believe him and was trying to deescalate.
2. Internally discussing the outcome of the call with other members on staff, they may have felt (1) was true, or Spez accepted the explanation but other staff didn't; they discussed the implications of each possible intention; and they collectively decided they should probably treat it as a threat since it remained ambiguous. It's possible Spez did want to believe him but other staff didn't.

The conclusion doesn't have to be that Spez believed him, then personally as an individual decided "oh, actually, fuck it" and decided to lie about it anyway. In fact I'd say that of the three possibilities, that's the least likely.