In Washington, a leak like this makes you ask questions. Who leaked the information and why? Then, US intelligence has had major failures, such as the supposed biological and nuclear weapons in Iraq in 2003, and you wonder how solid this information tortured out of criminals and militants is.
Also, in intelligence work there is always a problem of false flag tradecraft. Anyone could pretend to be GRU as a cover for such an operation. It worries me that the intelligence seems to be from the ground up, rather than the result of a penetration of the GRU itself.
Another question is why the GRU would have done this.
You could see a program to increase US troop casualties as an attempt to demoralize Washington and speed the US departure from Afghanistan.
The problems with that theory are many. First, there isn’t a need to give Trump a reason to leave. Trump has long wanted to withdraw all US troops from that country. He believes that the white working class resents spending blood and treasure there after all these years. He thinks he can run on getting out of Afghanistan as an accomplishment. High US government officials are trying to convince Trump to leave at least 1,500 US troops in country to gather intelligence. He seems to want zero troops there.