I had two new ships. One broke down in the Clyde and was rescued by a passing tug, and the other broke down off the Tyne in the middle of a Measured Mile which was in use by a BFO civilian tanker at the time. HMS Blake was stuck in the middle of the Pacific with no power for days .. If you can't take a joke ..
Although it has already been intimated (probably too subtley for your huge brain) anyone who does know won't be posting what they know here until the MoD ( that's Ministry of Defence - not Rum Ration's moderators ) have released details.
It may be that it is no big deal and the press see tugs and ropes and assume a vessel is not under its own power. If the media don't know something, they make it up and credit 'a source'. The boat may be in RN hands but she is still doing sea trials, the purpose of which is....? Go on, figure it out.