If true, that's a very stark shift. A 6% slump in party preference over the past two years, in spite of Annoying Orange's approval ratings, is pretty disconcerting.
16,000 people is also fairly massive as far as these polls go. Furthermore, 538 ranks Ipsos as having a slight Democrat lean.
https://projects.fivethirtyeight.com/pollster-ratings/But remember that you need to average
all polls, not just single ones, in order to get the most complete idea of how support trends are changing. This could be an outlier (not even necessarily due to bias, but just non-perfect random sampling from the pool of registered voters). Need more data from more people to construct a complete picture.
One thing to note is that the population of poll-bashers on this forum probably won't call that result bullstuff since it jives with their views. Not you specifically though, Kearn, since I've never known you to do that.
Poll