I will jump in on this one. I have the same bike and experience something similar. Mine doesn't go quite that high but will go to 2,500 to 3,000 rpm when first started cold. It will at first go to a slightly higher rpm than idle speed but will then climb up to the higher level for 10 seconds or so. The colder the temperature the higher it will go. If it is fairly warm it won't do it at all. I believe the bike is compensating for the cold engine start so that it won't stall. I don't find it to be much of a problem just a bit of an annoyance.
I also have surging mainly between 2 and 3,000 rpm, I keep it out of this rpm range as much as possible. These bikes like to rev so this is not a problem. I will probably take some heat for this but I have reduced this quite a bit with a Booster Plug with no ill effects as some will say it causes. Unfortunately there are no Beetle maps for the 1400. It has been noted that there is the potential to mess up, brick, the ECU on this model so a map isn't available. I hope this helps. I wonder if this is an issue with the Audace as I haven't noticed it with the very few other 1400s I have seen in person. The Audace is a different type of bike, maybe it comes with a different factory map than the more touring 1400 models.