I noticed the end/tip of the ejector rod sleeve , (close to the knurling) , was catching the retainer lug (on the barrel), when opening the cylinder. It only happened at a certain point in the cylinder rotation. It took me a while to figure out why it was harder to open at that point. So, I took some very fine wet sandpaper to that area on the ejector rod sleeve, and carefully smoothed it out . Now it opens perfectly on all chambers of the cylinder, and doesn't catch when opening.

I've read that sometimes the ejector rod is too short, and won't push the retaining lug far enough out of the way to allow the cylinder to be opened smoothly, or easily.

I don't seem to have this problem, but I see where it could create serious issues, and lead someone down a rabbit hole trying to find the problem, when it's a simple one.
It's amazing how precise these revolvers really are.

The center pin the outer rod and the lug tooth are actually all fitted parts. The end of the rod is often in the white on blue guns as the factory trimmed it to match the center pin. When the cylinder is out of the frame and you push the center pin flush to the center of extractor the other end of it should go just a tiny bit past the end of the rod. If not use a fine file to remove a little. Once I do that I take about a 3/16" drill pit and press it against the hole in the end of the rod and twirl it a few times with my fingers to give it a tiny bevel.

Occasionally the tooth will not press back enough for rod to move in. That is because its notch is hitting the pin before it can move back enough. Then you can either slightly shorten rod and center pin as described above or remove the lug pin and file the notch in it to allow it to move back a bit more. On the other hand if the tooth does not come out enough to engage the hole in the rod well, you can remove the pin and file on the other side of the tooth's notch so it will travel a bit more forward.

I have run into all these situations when fitting barrels, cylinders, center pins and ejector rods.

Like a revolver that has excess barrel to cylinder gap, first you remove barrel, cut .02777 off back shoulder it will thread in another complete turn, then trim the face off barrel extension to get proper gap, recut the forcing cone, then you have to remove that same .02777 off ejector rod and center pin

Did you check the yoke for being bent? when it is will cause your problem, if it worked find before either the extractor rod is loose or a bent yoke.