This happens. I believe the edge coming from the Chinese may have given you a false sense of sharpnes.
I like to explain this with my DMT fine. Sometimes, when I set a bevel on a DMT 600 I get positive HHT.
Well, we can all agree this wasn´t because of the extraordinary fineness and abality oft the DMT 600 to finish a razor (haha),
but rather a deceptive false edge. It may be possible that along the way to the finish you created a false and fragile edge
and by stropping you accelerated what was bound to happen anyway.

Another option is that your stropping technique is faulty, or your strop contaminated with some kind of grit (e.g. dust).
I agree with Sham and would recommend you to hit the Chinese a little longer.
You could even try to add one layer of tape and create a double bevel, or microbevel on the Razor
thus giving the Chinese a better chance to erase defects