Edit: I found this info and clearly my dog is in the third row “dog selective” category which is considered common. All this time, I thought a well-socialized puppy that got along with everyone would remain this way. This is such a relief to see this because I don’t feel like I have an unusual situation going on here! Clearly, I have to be careful upon meeting new dogs. But at least I know my dog is not unusual and there’s nothing to fix. It’s just that I have to change my expectations moving forward that she’s not the same dog she was when she was a puppy. I wonder why this info is not shared more? It must not be because I’ve done tons of reading on raising a puppy and I’ve never seen this.

https://www.reddit.com/r/Dogtraining/s/qa47Mi1Idg

Wondering if this is a standard poodle thing or rare for the breed?

My spoo is nearly 3 years old unspayed female. She has been well-socialized since puppyhood and gets along with most dogs she meets. But now and again, she’ll snarl and lunge at random dogs…and it’s usually dogs that are being super sweet and chill and show zero aggression towards her. In fact, just today she growled and lunged at a dog she used to play with regularly but have not seen her in about six months. And then last week, an unleashed doodle lunged at her on a walk and she was totally chill and did not respond aggressively at all. Before that, a chihuahua ran to her and she loved him! I have dozens of examples going both directions, so to speak.

We don’t do dog parks but speaking more in terms of meeting dogs on hikes or beach outings now and again. Sometimes she’s leashed and sometimes not. Doesn’t seem to matter. I never know who she will like or not like. It’s either dogs in passing or, unfortunately, unleashed dogs that we run into now and again.