I was trying many options.

Finally I discovered interesting solution. It does not make sense for me but works:

1. I have created additional filtered index (index_2)

2. checked estimated and actual numbers for index_2 - it was OK

3. checked estimated and actual for old (problematic) index (index_1) - and guess what - it have good numbers now!

Nice, but what happened after dropping filtered index_2?

- Estimated and actual numbers for old index (index_1) have restored wrong values (oO)

I have repeated the steps on additional testing DB and it works in the same way.

I wonder how to explain it.

Jacek