You may be correct here, I remember watching this on a screen (Covid era) and thinking when the names were read out concerning the Shore 4th IV, there were 2 new names from the 2nd VIII. I can't find the old Clutch video to confirm that was accurate or not. I may have been confusing the demotion of Wulff from the Shore 2nd VIII 3 weeks prior to the 3rd IV and I thought it was another name like Clapman in the 4th, but I can see him listed in the 2nd VIII, so my apologies.
According to the listed names it was half the Shore 3rd IV moved into their 4th IV within the last 2 weeks (Mathur, Knapman), it enabled this Shore 4th IV combo to speed up their 4th IV and win, a time over 5 sec's faster than their 3rd IV. Was it stacking, probably not intended to be, but you can see how it would be interpreted as such.
My point is Shore can't claim a high moral ground here and accuse Kings 2nd IV last year or View IVs, when they have made similar moves in the past. Schools are trying to find their fastest combinations, within reason most of the time.