"SID" doesn't really exist for event Pokemon like it used to, due to the gen 7 changes. If you look at the FID (full ID; combination of TID and SID), a pattern quickly emerges. It's one of two things: either WCID is placed in front of the intended ID No, or it isn't.
The FID for these events is 20218, or 0000020218. The game hides all except the last 6 digits, so we get 020218.
Meanwhile, an example of an event that does have the WCID in front is the NA/PAL Marshadow. FID is 0626100917. Its WCID is 0626, and visible ID No. is 100917. See the pattern?
Basically, they don't just pick a random TID and SID to get the ID No they want. They just pick a FID they want. The TID and SID visible in PKHeX are derived from that.
Anyway, as for these events, I think they've only changed a test WC to include the WCID in the FID once before, so I wouldn't expect it to change here. It's possible, though.