I don't think they were. SSS wasn't given the HW-era Empyreal Arrow treatment until Endwalker, I thought, which is what the added portion of the tooltip seems to imply (that it incurs but does not respect the GCD).
If the tooltip isn't errant, its uptime cost would be <an animation lock short of a GCD> less than it used to be and yet its potency remains the same.
That is to say (again, if the tooltip isn't an error), assuming we had a 2s GCD before, we've gone from an effective uptime cost of 4 seconds to a cost of ~2.5 seconds (with low ping, as animation lock variance from ping is now relevant), at 550 potency (edit: listed at 500 online; 550 is only on the job guide).
Maybe if I could log in at some point during Early Access, I could test said tooltip... (My hunch though is that the tooltip is bogus, either in having the same descriptor as old pseudo-GCDs or in its potency.)