Beaming in 3/4 time

[Madiel]

Number 2 only looks like 6/8 time if you insist on ignoring the fact that it says 3/4 at the front.

It's as simple as that. You're not supposed to look at one tiny bit of the score without examining the context. It's like arguing over whether "rebel" is used as a noun or a verb without looking at the rest of the sentence to find out.

[Madiel]

This is however one example that I find ambiguous:

I always found the dotted quarter-three beamed eighths to sound like 6/8 here. Obviously the time signature is 3/4, and later passages in the movement are unmistakably in that rhythm. But there is nothing in the string writing accompanying the oboe/clarinet melody here that would clearly suggest 3/4. And the conductor cannot make accents to emphasize the 3/4. Intentionally or not, this passage feels like a rhythmic ambiguity to me.

Being rhythmically ambiguous may well be the entire point.