That's interesting to me, Rob. I've found exactly the opposite to be true for me. "YMMV" can not be expressed more aptly I guess.
Granted, honing on flat stones is edge leading whereas stropping is edge trailing, but I've never rounded an edge when honing, and I've never rounded an edge while stropping on a flat surface. Rounding an edge on a chrome pasted hanging strop? I sure have.
The only way I can see coming close to rounding an edge when I've stropped on a flat surface was when I laid down too many sheets of newspaper on a flat stone. I provided too much cushion and assumed that the deflection and cushion of the newspaper was touching the edge during passes rather than strictly the bevels. I use two layers of newspaper cut into square sheets taped firmly to a hone when stropping and I've never come close to rounding an edge.
Can you go into detail about your experiences?
Thanks
Chris L