The problem with it on here is not that you can't stun lock a player, it's simply that all damage done to a person while they would be getting "speared" is completely cancelled, meaning you literally can't do any damage at all during the spear spec duration, only once it is gone. The "few seconds" that you can get off on RS is enough for any clan to secure a kill, however that is not possible here since you simply can't do damage to someone during a spear spec.
Tested this and was still able to damage the player during the time that they were stunned. Not the best GIF, but you could see a 1 damage XP drop, and then the 1 damage hitmarker appears upon unstun:
https://cl.ly/daf47cc67aa8
Perhaps you meant that it only happens if there are many hits going through, and some end up getting canceled out? (4+ during that time of being stunned, I believe 4 is currently the max to show in 1 tick)
I also think that the magic delays you guys are talking about is also a ping issue, anyone who isn't from North America will experience this. Here is how it looks when I was testing:
https://cl.ly/fbf0bbfaa308
That looks fine to me (virtually no delay), but I understand it isn't like that for all of our players. We'll be improving ping for EU players later this month as well though, so hopefully that'll help smoothen things up a bit. I'll have most of this list done in the next update.