Bug with prices and total sum in cart ( recalculation of prices and promotions)

Hi, alls

First of all about my system:
Drupal 8 + commerce 2.24 + for quick generation of goods: commerce_demo + belgrade theme

I've faced very strange bug\nuance in my shopping cart.

Straight away a link to a video illustrating the problem: Click

1. I created a 15% discount on all products after the total order exceeds $100 (for example).
2. manipulations on the Cart page:
   • When I increase quantity of my GBP up to 7 units - everything ok (every product gets a 15% discount and total sum = $101.99 ).
   • But when I decrease the quantity of GBP to 6 units I get a very strange result - $109.99 and all prices without any discount!

   Given the $ 109 amount, I expect a recalculation of the prices and the total.

The correct situation (6 units of GBP) should look like this:

- all prices are recalculated with a 15% discount

- the total amount is $ 93.49

Apparently, with a decrease in the quantity of goods of the GBP, the total sum is reduced to less than 100 and all prices are recalculated
to the base values (without discounts). But It is logical after that to make another check of the received total sum for the promotion
condition, but this does not happen.

In addition to changing the number of certain items of the product, the same problem applies to the complete removal of the product from the cart

maybe there is already a solution to this problem?

I would be grateful for any help
best regards,

Savage