It is a semantic distinction, cover up versus down play. You do not cover up a tragedy by sending both civilians and military to find and retrieve the victims. You can down play the tragedy by wanting to exert control on the final services. This happened.
The Soviet government, if anything did not bring the awareness of a hiking accident into the national spotlight. That would lead to criticisms of the system, especially when the Soviet was instituting programs to promote world class youthful excellence in sport. That said, heads did roll in the aftermath in that period of adjustment where someone had to shoulder the blame. This was in the organization or sports club Igor and the others belonged to. They, the DP9 if all went well,could even earn certifications culminating in Master of Sport. The government was all for it.
On the other hand, when such endeavors end badly, there is little incentive to make a big deal out of it, unless the story can be spun into a tale of heroism, like an astronaut. That was not the case here. In fact, it was somewhat the opposite. Hikers took on a winter challenge poorly equipoed, supervised and against local advice. Other than bragging rights to have rounded Ortoten in winter, there was not much to crow about. This failure could be seen as a random chance event, hubris, but not heroism. The deceased were treated well and laid to rest with love and ceremony. The treatment of the case was certainly not a cover up, it was known then as well as now. We all understand there were aspects of the case which raise our eyebrows, but these were sins of omission, rather than deliberate obfuscation. It was down played as an unfortunate circumstance where I contend unprepared hikers were caught out by a slab slip, hypothermia and a collapsed temporary shelter. Again, to my point, a down play, which is being quiet about unfortunate truths is not a cover up which is the deliberated obfuscation of evidence to hide a homicidal conspiracy.