Whenever I use RTV, I let the surface skin up before I assemble the parts. Its still gooey underneath, but it is less prone to smearing out of place while joining the parts. If you had done that before putting the intake on, you could have noticed the problem. My hindsight is 100% flawless, ain't it?
If it were mine, at this point, I would leave it alone for another 2-3 days to see if it sets up. If it doesn't set up after that, then I'd take it back off and buy some Black or Gray High Heat RTV (my two favorite go to products) and reinstall the manifold. I am not suggesting that the copper RTV is not a good product. I am saying that I would now be superstitious about it after it failed on me. Superstitions, while scientifically invalid, make me feel better about myself so often that I succumb to them from time to time. This would be one of those times.
Give it a couple more days, don't walk under ladders, nor let a black cat cross your track. It may set up.
Carl
