Answer:
The main unintended consquence of the policy of glasnot (which means "transparency" in Russian) was that it led to criticism from the nations of the Soviet Union, towards the central leadership in Moscow.
Leaders in the Baltics, the Caucasus, Central Asia, Ukraine, and Belarus began to criticize the soviet leadership in Moscow. In these "peripheral nations", people felt that the central government was pro Russia, or that they were essentially russian colonies.
These criticisms devolved into full blown rebellions, which led to the break up of the Soviet Union by 1991.