perhaps this is what is being talked about ....and perhaps overstated ......

Ukrainian army says some Russian troops withdrawing from Vovchansk area

Some of the Russian forces are withdrawing from the area near Vovchansk in Kharkiv Oblast for replenishment due to a loss of combat capability, the spokesperson for the Khortytsia group of forces, Nazar Voloshyn, said.

The withdrawal of Russian units was also seen near the villages of Lyptsi and Tykhe, where the Russian armed forces suffered losses, Voloshyn said.
https://www.yahoo.com/news/ukrainian-army-says-russian-troops-170646324.html

It does seem like russia are fighting defensively in the Kharkiv area .