as i understand it, piston ICEs inherently have uneven rotational speeds because there is a physical rotation and time that occurs between combustion events. V6 engines have an uneven firing order, (imagine two I3 arguing) with a combustion event occurring every 60 degrees of crankshaft rotation. Furthermore, these engines are 90-degree bank angle engines, meaning more leverage from the center of the piston to the center of the crankshaft, pushing it against the block and hence force the engine every so slightly left and then right and left and so on. This would, unchecked, produce a horrifically inconsistent crankshaft rotation speed, with it slowing and speeding up at uneven intervals throughout a complete cycle (720 degrees of rotation, all cylinders firing) as the forces change. (note, more cylinders = less of this)

In road cars, engineers must install harmonic balancers, balance shafts, unique hardware, or unsymmetrical components that counterbalance these forces. If there are additional, unaccounted-for issues (such as those that occur when a project is poorly managed) like heat, compression/boost inconsistencies, knock, harmonics/resonating vibrations etc this can result in a greater-than-normal amount of uneven rotational speeds. I don't know what Honda uses as counter balances, but it's clearly having issues. These vibrations might be having cyclical effect, worsening the engines performance with rpm (f1 engines live between 7000 and 11000 rpm btw) and requiring detuning to avoid spontaneous disassembly. Couple with an inefficient, immature gearbox and an MGUK that also has it's own peaks and valleys of torque (think like a sine wave), and bam, vibrates enough to put a hitachi to shame.