Bob,
That's good news that it's dropping slower.

When my second pond was being built mid December of 2016, the builder did not have access to a roller. I had him use his large (10 ton) backhoe with a full bucket of clay to run over things and pack after it was mostly done, especially in the deeper basin.

It filled slowly at first, then we got good rains spring of 2017 and it went over the spillway twice, but leaked down a few inches fairly fast. It continued to slowly leak through last fall and winter drought, and had dropped 22-1/2 inches by late February.

Then substantial rains came late February this year, put it over the spillway. After it quit running over after a few days, I looked at the places where it had been seeping, and very little water was there.
It stayed up within six inches of full for a month with no rain, then went over again in late March rains, and dropped only about 4 inches in April despite way below normal rain.

After the early May rain, it is full again, and only dropped an inch in a week of above normal temps and wind.

If a clay dam is not fully compacted, sometimes it will settle over time and begin to hold. The last time I looked at the former seeps, only saw a little dampness.
The mud washed into a clay pond with the first few fills will sometimes clog seeps, and that along with settling of the dam makes it better.

So, my second pond is holding better and better.

It may have helped some last summer and fall when the farmer who gets my hay drove his heavy tractor and round baler around the dam to get to the lower edge of the field. He made some wide shallow ruts on the back part of the top of the dam.

Leaks where actual water flow is observed probably won't ever fix themselves, but wide seeps can sometimes get better with time.

Maybe this can give you some hope, Bob.