Oh, they most certainly did - and thank God they did so. But it was not an invasion, it was an annexation to put a stop to the pogroms that were being carried out by NAZIS against the Russian populace.
The Yatsenyuk government passed laws outlawing Russian as an official language. It made other changes that were decidedly aimed at excluding and persecuting the Russian speaking Ukrainian population.
There were demonstrations and acts of rebellion in the Eastern provinces of the country. These were put down by the Nazi thugs who had provided the “muscle” for the putsch in Kiev.
In one infamous and outrageous instance, the far right group Right Sector burned 39 protesters alive in Odessa. It is a gruesome story, but one that had many analogs take place all across the Russian speaking areas that refused to accept the Coup government in Kiev.
Burnt alive in Odessa (documentary)