We've had our 2006 FEH 4x4 for about 18 months, meaning we took it through a NE Ohio non-typical mild winter last year. However, with this winter's early harsh, cold blasts, we've seen a significant reduction in mileage, both per-tank and per trip, that seems to be tied to the weather (from a typical 29-31 down to, currently 21.9). As well, we've experienced a rather odd phenomenon: On cold start, the ICE has been "revving" far more than typical for its little self, and in odd ways. While the transmission is a CVT, at lower speeds (sub-40), the RPM's stay high, even when the engine is not under load, almost the same feeling one would get in a typical automatic transmission where the car is "hanging up" in second. Once beyond 40 mph or on the highway, it returns to a relatively normal state.
We took it to the local Ford dealer suggesting that it might be either a faulty IAC valve that needed cleaned or replaced, as no trouble codes of any kind came up, other than the odd RPM issues. The dealer came back with a suggestion that the entire throttle body needed replacing to the tune of almost $800 ($493 for the part alone). A little research suggests to us that the throttle body is likely not the issue, and we've not returned to that dealer.
Add this: When it's doing what it's doing, putting the can in neutral or part and attempting to "rev" the ICE gets virtually no response; however, the ICE responds normally to the same action when going down the road.
The Escape a monster? My Camry is about the same weight, and is longer.
For the OP, you say cold start, so I'll assume the higher revving stops once everything is warmed up. That is likely normal in order to get everything up to temperature. I've the behavior in a 2013 Sonic, and hybrids addressed start up emissions earlier than other models.
As for no revving in neutral or park, the car is throttle by wire. It knows what gear you are in, and likely sees applying gas in N or P as a waste of gas More likely it is avoiding high revs without reason to protect the engine during warm up, or to avoid cooling from extra fuel being dumped in the cylinder.
I have extensive knowledge of the FEH... I had one for many years until it was totaled. A couple of things can cause the issue you describe.
1. A severely cold battery pack. (pack is under 30F). If the pack is very cold, the amount of current allowed in/out of the pack is limited to avoid damage to the pack. This can restrict, or even completely shut off the electric assist that helps the vehicle move from a full stop. If electric assist is disabled, the engine will rev high, and acceleration will be very slow.
2. A low State of Charge (SOC) in the battery pack. If your pack is low the engine can/will rev high in attempt to charge it. If the SOC of the pack is low enough, electric assist is also cut off.