Help with a circuit design

I will be grateful for any suggested solutions to this problem

When you draw, it is good to have the most positive voltage on the top and the most negative at the bottom. Often inputs on one side and output on the other.
I added a second diode and a 1k resistor. When power is applied they have no function. When power is taken away the capacitor will discharge at 1K rate not the 10k rate. (10 faster) This should help your problem.

Thank you so much for that.

Apologies for the schematic protocol failure, I cut and pasted the portion from a larger circuit.

Suffice to say, I wouldn't have figured that out alone. Thanks again.

The 1k is there if you don,t have a load on the 12 volts. If you have enough load the 1k can be removed.