I can see a non-estrous doe avoiding an estrous doe but would she blow at one? That's pretty much a warning to other deer to stay away. Maybe she thought the estrous smell was too strong so she thought (rightly) something was up.
I'm guessing it was a warning to the "estrus doe" (really the tag) she was scenting to stay away, unless she'd detected something else altogether.
I must admit, though, that I have little knowledge of deer calls and am only speculating. Perhaps this is something to experiment with and see. Could be useful to know.