Anna,

You said Bon has been getting along fine with other dogs at the park until this incident, but also mentioned that other dogs would
seek him out. Were the other dogs acting playful? How did the
interactions go? Were they just sniffing him out, etc. ?

If any previous encounter was a bad one, he could be re-acting to that by being on guard with newer dogs for a while. I'm sure
, if that's the case, Carrie , Candy or Aly could offer good advice
on how to overcome a bad experience. Hugs to Bon, Roxy & Huney.