As a new section NCO, what would be the best way to deal with squad leaders who skipped the chain of command (myself)?

You need to tell them they need to go thru you so you can grow and learn as a new leader. We all learn by our mistakes and good choices. If they never give you that opportunity how do they expect you to grow into a better leader.

I'm trying to understand the scenario.
_If your juniors skipped you and went directly to the Plt Sgt or Plt Leader, barring some immediate urgency, the juniors should have been sent straight back to you. In that case the Plt Sgt and Plt Ldr are failing you.

If an NCO senior to you, but junior to the Plt Sgt, is jumping in downline from you. It isn't your place to "correct" them. But I'd ask that senior NCO what gives? In this case apparently the Plt Sgt and Plt Ldr know about it. If they do it is their place to correct the NCO who is stepping on your toes. Once again, the Plt Sgt and Plt Ldr are failing you.

I've had to jump the chain a few times, and was even apologized to for being put in that position.

Communicate. Make sure your soldiers know who you are and what they can expect from you.

Know your job. Just because I don't know something doesn't mean I can't tell you don't know either. If you're unsure and don't communicate (that word again...) your efforts to learn or master it, I don't have the patience for you to fix your own incompetence. If you have to tell me you're in charge more often than you show me, you're failing to communicate your leadership.

Watch for bias. Soldiers who appear more or less competent, soldiers you enjoy talking with, soldiers who drive you up the wall, you need to work with all of them; none of your soldiers are your friend or your enemy. Likewise, don't favor yourself. Your rank really is just a splash of ink and some thread unless you put in the work to make it otherwise.

Have a mentor. You can only get so much advice online. You need someone who knows you and what you're going through personally.

The first thing you need to do is make sure all your paper work is correct. To start with if you really are a corporal ( I.E.) having been pined with orders. His your first N.C.O.E.R. been done? This should give you all off your responsibilities 1.What is expected of you. 2. Personal you are reasonable for. 3.All Equment you will be responsible for as well as the paper work that goes with them. Now to the question of skiping the chain of command. what rank is the person that is skiping you, And what was the issue you may not have the experance to deal with it. What I would do is tallk to the Person that went around you. Talk to them on the side. Remember the rank structure, Simply ask why you where left out. Like I said before you my not have the experience or knowledge to deal with it. Or the just was not time to bring you in. Keep all these thing's in mind. Some N.C.O's that outrank you get butthurt whenever they are questioned. Tack and being respectful can go a long why.

The issue is you go over their head; all of a sudden, the immediate supervisor, who is clueless when asked by their superior, is in your case. It rolls down hill; similar to an Congressional complaint.

speaking as done so myself, good or not so good, be ready to except the consequences from a harsh
rebuking to the loss of Rank.

you must go thru the chain of command .. there is no other way but do that correctly .. unless you are the p. i . c. private in charge of a squad platoon, etc. then you MUST still go thru your up-line C.O.C. read the regs ,, ask around to some of us seasoned active and Veterans they will tell you the same as i .. good day Private.