too high compression?

Not knowing your car nor your system, here are ,I hope, some helpful tips;

On period Mopars;
EGR was limited to Part Throttle.
no EGR was allowed;when cold, at idle obviously, or when accelerating briskly, and not at WOT.
There are multiple controls to limit EGR to more or less, a cruise only situation.
Since Exhaust gasses are inert, they do no harm in the chamber when the system is operating properly. Their job in there, believe it or not, is to reduce the temperature of combustion, to reduce the amount of Nox created; a stinky harmful to the atmosphere,pollutant . Which is also partly why the Scr is in the basement.
But in my estimation, they also serve some other possibly useful functions.Since they are inert, and they occupy space, and they are sucking up heat in the chamber, and they are homogenizing the mixture;
1) the reduced temperature should reduce the propensity toward detonation., and
2) when the fire lights off, they become a bit of a shock-absorber in there, and
3) they should increase the Effective compression ratio.

Having them in there at Part-Throttle is no big deal, except that the throttle has to be opened a little further, to compensate for the power loss caused by the lowered combustion pressure, caused by the reduced temperature of the expanding gasses.

IIRC, in the beginning, on Mopes, they were controlled by venturi vacuum, and a vacuum amplifier system. This made them very sensitive to throttle position. And of course, throttle position is somewhat dependent on ignition timing, and cylinder pressure.
As the engine gets older the pressure drops, and it takes more and more throttle-opening to accelerate and to maintain a given speed.
Also, if the timing goes away, the power also falls, giving the same results.
And the greater throttle opening, increases the venturi-vacuum signal, which the amplifier dutifully magnified and opened the EGR valve further, reducing the power, and you can see where that's gonna end up.
On Mopes there was a Thermo-vacuum switch in the stat house or the rad, that was calibrated to eliminate EGR below a certain coolant temp. If your engine never came up to temp, you never got EGR.
If your throttle opening at idle is too far,say because of engine load, or retarded ignition timing, or retarded cam-timing, then the throttle may be in danger of activating the venturi-port.
You may not be able to check the cam-timing, but if your engine has a valve cover,you can always check split-overlap.