I think it's just sometimes. Maybe in mostly foggy areas. I haven't played ton, but I didn't know if the monitor being 144hz would effect anything.Is it stuttering all the time or in ceratin areas only? It seems like they did something to it because it doesn't feel as smooth. But it could be because I saw people complaining about it and hadn't noticed it before.
There is a good performance discussion here: https://www.resetera.com/threads/digital-foundry-rdr2-2-ps4-pro-xbox-one-x-1080p-fake-hdr-analysis.78182/post-14432211