Easy to speculate, and maybe a bit of fun to do so, but without full information it's also very easy indeed to come up with entirely the wrong answer which as I said may be a bit of fun to the casual observer. Looking at the plot however shows some consistencies such as the course at the eastern end of the plot, and that immediately following the round(ish) turn to port. That tells me that the ship was attempting to follow a charted course. Next are the distances between successive positions shown in the plot which tell me that whilst some speed was lost during the manoeuvre, overall the ship's speed remained relatively constant, and 12.8 knots is not a lot for that ship. That suggests to me that the manoeuvre was probably not as a result of steering or other failure where one of the first priorities would have been to stop the engine and take the way off the ship. Altering course to port for collision avoidance is unusual, if that was what they were doing, but may have been related to a situation about to be encountered and the final course alteration at the western end of the plot and where a consideration may have been to alter course early in order to avoid such situation. Clearly something has happened, or has been desired to happen to cause, or result in the course deviations, but unfortunately there are no similar plots shown in this view of what all other vessels including those not shown were doing where they either did not have, or were not transmitting an AIS signal. Examples of such vessels may have been a group of fishing boats, yachts or military ships, and where their actions may have been the primary reason for that manoeuvre. The final change of course at the western end of the plot suggests to me that the ship may have turned to begin the run across the channel while heading towards the separation zone off Ushant (Ouessant) and on to wherever their cruise destination may be.
Lastly, "Scheduled for Zeebrugge?" Well they may have simply been wasting time in order to arrive for a specific time or tide, but I have also seen where ships staff have forgotten to re-set their destination on the AIS prior to leaving a port, one of which was a ship I was waiting to visit and which lead to a short conversation when I got onboard !!
But it sure can lead to some speculation as to what was going on 👮
P.S.
Wasting time was the best bet - thanks Marine Traffic👹
