In VTK export we have , when assigning numerical values for the BOUNDARY export:

for (size_t i=0;i<size;i++) {
	small[i] = (NodeType[i] & it.flag) >> it.shift;
}

So the minimum value would be 0.

Meawhile in cbRunR.cpp we have also for BOUNDARY:

for (size_t i=0;i<size;i++) {
	small[i] = 1 + ((NodeType[i] & it.flag) >> it.shift);
}

So it will start from 1.

This is not a bug I think, just inconsistent behaviour, not sure what to do with this. Occurred to me when passing BOUNDARY values from R to Python and trying to filter by numerical value (which was off by 1, because I was using the value I remember from VTK export).

Not critical, just wanted to document somewhere.