I know of a number of parishes that changed over to Orthodox.  But there were also other politics involved.  There was a concerted effort on the part of the Russians to get Ukrainian churches to stop being Ukrainian.  Although I do not doubt the genuineness of many in the "Rusyn" movement (not quite as vocal now as in the past), the origins of this had a Russian (and sometimes Hungarian) hand, because Ukrainian "nationalists", a term that was applied to just about anyone who recognized their ethnicity, were considered to be especially dangerous.  
I find the entire history of this to be very interesting.