On November 17, 2015 at 15:12 MSK (12:12 UTC) the Strategic Rocket Forces carried out a successful launch of a Topol/SS-25 missile from the Kapustin Yar test site. According to the official statement, the purpose of the launch was "to test new combat payload for future ICBMs." The warhead was said to have successfully reached its target at the Sary-Shagan test range.
Previous Topol launch from Kapustin Yar took place in August 2015.
Comments
Tests of the Sarmat ICBM will take place in Plesetsk:
http://tass.ru/armiya-i-opk/2443873
What happened to RS-26 exhibition in Votkinsk?
http://tass.ru/armiya-i-opk/2448395
Maybe they know that the U.S. will have a proof that RS-26 is not quite INF Treaty-compliant, so they decided to postpone it, so it won't spoil the brief "sort-of-a-thaw" moment.
Likely RS-26 deployment is delayed by a year to 2016.
US never had any issue with RS-26 but more about Iskander system not being treaty complaint
to Austin Joseph:
Yes, this is most reasonable explanation.