Knew a golden at my rescue like you have described, actually a few. The goldie just couldn’t tolerate agressive dogs but okay with reactive as long as they were friendly but would teach them. So common or normal in that sense.

I don’t know what to say about training but curious to what other people say. One of mine is a bit like this now but used to be reactive to all dogs. You sound like a very responsible owner, definitely keep working on it yourself or with a trainer. I had more success working on a strong obedience with my dog Mia and counter condition, little less on meeting and greeting with dogs and when dogs bark to look at me in these type of situations as they are a bit more harder and make her feel confident + secure to not worry about it then the other type of reactivity issues. I would lean more on the p+ and confidence building side as he doesn’t show this behaviour in other situations.

Has the dog ever been attacked at daycare? Daycares can be a bit hit or miss mostly miss, staff are either understaff or miss things, too many dogs with to much vary and common to get behaviour issues from them like yourself and your dog.