Not on a STTNG but it's a common occurrence with these aftermarket ramps. Some messaging is necessary to get things to line up perfectly again. Also, check if you have any switches on the ramps. Sometimes they need to be adjusted in order for the ball to make good contact with them due to the extra thickness of the ramp walls.

Good news about the new ramps are they are thicker so they should last longer.

I have not replaced mine but I would agree replacements are usually thicker. Also, the spacers etc. may not have been correct to begin with--I ran in to that on a TOTAN--I scoured the web for pics of the correct post/spacer placement. I've used a dremel to shave some protectors--haven't done it to any ramps...not sure if any of those solutions help. Maybe search for STTNG shop pics and compare things?

It's funny - I had the very same problem that you have! I also replaced Alpha and Delta at the same time and the diverter was not able to go through the opening in the Delta ramp. I remember it was certainly at least 5 mm under the opening. I do not know exactly what was going on, I even removed both ramps and placed them in there again, but after inspecting the situation and not knowing what to do exactly I tried pressing it down on the rear part again and again for half an hour. Suddenly I heared a short loud scratching sound and the delta ramp was moving down the required way instantly (nothing cracked by the way). I can not fully tell you what happend exactly but I think the space for the Delta ramp is too tight as the material of the ramp is slighly thicker and it was just frozen on the backboard. I would recommend to sand off the side of the Delta ramp (maybe the Alpha ramp, too) that is touching the backboard a little bit. Moving the diverter up is not a good thing (I think) because it would mean that the ramp is too steep which would result in a changed game play or in the most worst case maybe impossible to do certain shots.

The only problem I have after the ramp change is that the delta ramp flap is not exactly in the same angle and position on the playfield as the old one so the mold of the old one is slightly visible in front of the new flap now. The metal of the old flap digged into the playfield over the years. I do not want to paint the playfield there, it would just be easier if the new flap overlaps the mold of the old one (which is the case on the new Alpha and Beta ramp). Any idea how to do this or how to hide the markings?

How did you solve the problem with the delta ramp sitting to high?