I know this says "Stern game" but it is likely your problem. Just had this problem and fixed this way on my EBD upper left. Also felt "magnetized" changed out coil, stops & sleeve's. Issue came right back. Raised flipper and used the flipper spacing tool (Titan Pinball) and its fixed

Somewhere earlier I saw someone post a fix. Then I did it to mine and it works perfectly for both sets of drops IF you dont have the adjustable mech version. It is simple and easy. I cut a piece of cereal box top the length of the drop mech. the box top is now roughly 6" by 1/4". I put two pieces of double sided tape (each tape piece probably 1/4" by 1") under the cut box top corners and placed in in the bottom of the mech. Now when the drop targets drop, they are resting on this cardboard, not the bottom of the mech. So it raises them up the thickness of the box top. For me, one strip of cereal box top was exactly the right amount raising the top of the drops, when dropped, exactly level with the playfield. No more issues.
Will snap a pic, later, but it really was as simple as cut a strip of cereal box top, and tape it to the bottom of the mech under the drops so that they rest on it when down.
You might need more or less adjustment, ymmv. 5 min fix.

EBD Drop shim 2 (resized).jpg

EBD drop shim (resized).jpg

One piece of box top cut to the length of the mech worked for me. Mounted it with only a small bit of double sided tape under each edge.
Once piece was the right height for me. You may need to experiment with thinner or thicker paperboard. But one piece of cereal box board was perfect for mine.

Also, two thumbs up for Yopsiccles. My 81 EBD was a basket case. Did a complete rebuild with CPR playfield, etc. But switching to Yoppsicles was the best part of my upgrade. highly recommend.