Lately the cursor positioning has reverted to its earlier bad behaviour where it would float a position ahead of the insertion point. Now it seems to do it only when you go back over your work to correct, insert etc. Pestilential.
I note, too, that multiple spaces in pasted items again cause invocation of the Code Snippet Detection monster. Or something is.
And I am a rare beast... I don't tweet, or stuff about on facebook. That popup is an annoyance, not because I must click to remove it, but because I think I loathe heartily what it represents, and that is people seeming to want to have a say about anything and everything whether their point is germane and interesting or not, and to be noticed. I could go on, but then I'd be blogging. Echh.
What happened to hermits?

Can you give me some exact steps to reproduce this??

Sure, Dani.
If I try to correct something I have typed by moving the cursor back to that point then the action will occur one position earlier than indicated by the cursor. At point of typing.. ie the end of the current string of text then the cursor is correct - in that action it appears to be unaffected by anything after a NewLine <CR> character. But there is another effect I am trying to nail down... haven't got it, yet.
Something else... if I use the back arrow [cursor left] key then the first press is ignored, but not if I have already moved it by mouse.. ie that only happens at the end of the typed string. And if I correct the last word in a line then the cursor will sometimes jump into the first word in the next line. And some words will not let me place the cursor inside them at all!!
That is just for starters... the anomalous cursor effect is more involved that I have indicated.
I am using Opera.
Further if I attempt to post something with more than two spaces in succession then code snippet detection occurs.
This is ridiculous... I shall try a restart of my sys.

OKay, it looks like a conflict with/inside Opera. It exists still. For example, if I copy my post above and then try to position the cursor inside the word "sometimes", it will only go at the beginning, neither arrows or mouse positionning work correctly. In the original post, it was the word "ignored" and a couple others; they work in the copy.
Everything is fine if I use Firefox.

After re-installing Opera 12 I am testing again. No change.