Unwanted text string "data-cke-xxxxxxx..xx" before text starting with "on..."

[tenchiro]

After upgrading to Chamilo 1.11.28, strange texts started appearing when creating NEW text-based articles. In my case, when I create a new "Rich Media Page" in Documents. (Based on comments from this link, the same 'bug' also affects QUIZ.)

The text always has the prefix of 'data-cke-alphanumeric'. I first noticed it before any word with "online" (Ex. 1).

• Ex. 1: I am o, I am data-cke-67993840babdd-on, I am data-cke-67993840babdd-one, I am data-cke-67993840babdd-online.

After subsequent testing, I can now confirm the texts will appear (appended to) any word that begins with 'on'. See examples below:

-Ex. 2: I am ob oc od oe of og oh oi oj ok ol om data-cke-679938d3e33cb-on oo op oq or os ot ou ov ow ox oy oz data-cke-679938d3e33cb-on

Notice that in Ex.2, only words starting with 'on...' are affected.
Editing the Rich Media -- i.e., removing the 'data-cke-...." may correct the error, but sometime, the bug may persist.

Any help on this problem is appreciated. Users (students) are noticing the error texts 'bug' and it is embarrassing in class.