Putting a sequence of negative values to INT32 RLE-encoded column corrupts the data after compaction.
The exact recipe to reproduce it is following:
1) Put a sequence of negative values in descending order to an INT32 RLE-encoded column (it's a primary key in my case, but maybe regular columns are affected as well)
2) Wait for compaction
3) See you data converted to -1's
A Gist showing an example of data corruption is available here: https://gist.github.com/pmaciolek/dfc6a95ff85145d23774cb5d1a9f5a4f (based on sample.cc provided with Kudu sources, note that -std=c++11 might need to be added to the compiler flags)