Not a mistranslation, and nothing was added. The Greek κηρυχθέντος uses a past (aorist) tense, and that is rendered by an English past tense. But "proclaimed" might be a better word than "preached."
Colossians 1:23: "if indeed you continue in the faith, stable and steadfast, not shifting from the hope of the gospel that you heard, which has been proclaimed in all creation {or: to every creature} under heaven, and of which I, Paul, became a minister." (ESV)
This verse may be referring to the event of the Resurrection, or it may refer to the gospel being preached everywhere.
Again, you are incorrect (καθὼς καὶ ἐν παντὶ τῷ κόσμῳ does mean "as also in all the world"), but there is a question about where the commas go. A better translation is:
Colossians 1:6: "which has come to you, as indeed in the whole world it is bearing fruit and increasing—as it also does among you, since the day you heard it and understood the grace of God in truth" (ESV)
That's not what the Textus Receptus says, and it's a nonsense translation. The only difference in the actual Greek Textus Receptus is that the words "and increasing" are missing.
