[BUG] Nested replies & post numbering / nav widget

[UPDATE] Well, I just went back & checked these replies while making/editing this post & they're now nested, but also appearing later in the thread, see this image, the post after my reply to post #294 is #365:

so I'm very confused. However, the other issue of the post numbering is still occuring, I'm wondering if it's just me? [/UPDATE]

I thought I may have been replying incorrectly when several of my replies to specific posts were added to the end of the thread instead of the post I replied to.

The only specific example I can think of is the "What new stuff have you bought recently" thread, I posted to the end of the thread:

And then replied to this post by hvm_kim:
But this reply was added at the end immediately after my own one. This has happened a few times, another example I can think of was my reply to turin321 about his Ubuntu phone:

And in making this post I noticed another issue:
Discrepencies in the exact URL & post numbers of my & hvm_kim's post, hvm_kim's post I referred to showed as #291 in the little nav widget to the bottom right on the page, but I believe it's actually #294 because this is #291:

I pasted this URL into the address bar & hit enter, I ended up the same post by QwarkDreams but the URL decremented by 1 to 290; :-/

This is all in Chrome, so I cross-checked in Firefox but got identical outcomes.