I think they don't like any changes to their meat wave staging plans. Manoeuvering requires trained troops in contrast to unrefined frontal assaults.
Let's see how they can manage. That was one of the points I saw in the incursion, create freedom of movement and complications for the cumbersome Russian army and their non existent (useful trained and equiped) reserves.
The article below also takes this into account
The deep Ukrainian offensive into Russia's Kursk Oblast is becoming a watershed and opening a new page in Europe's largest military conflict since 1945.
neweasterneurope.eu