The 3X input is 8mm wide in the clear, so from a 3E or G2 to the 3XBE input I doubt would clip, but it could over expand and clip at the output lens which is 25mm and the expander is actually 3.3X .......actually I would be surprised it clipped much at all.
I see clearance on both sides although from the camera angle it looks like the diode is possibly pressed a bit crooked or maybe the adaptor was not fully seated, or that BE could be out of parallel, but I do see both edges and the 8mm wide input clipping is not likely over that short primary to input distance.
How wide is the exit of a 3 element lens....5.5mm, the divergence out of the primary would have to be ridiculous to clip the 8mm input only what, 1/2 an inch, maybe 3/4 away.
Is the red diode more divergent than the NUBM44 ? it's the same at the worst I do believe.
Here's a NUBM44 with a 3 element printing on a 3XBE, it clears both sides.
Even if a 3 element clips the red diode which they all do, it's part of the reason for the 70% power transmission, it's worth it on my 638nm because it looks so much better, I suppose a G2 could clip, but I wouldn't use a G2 with a 638nm without cyl correction anyway, the spot is a really ugly long line/rectangle.