I just checked, it's just like you said.
As you pointed out, it is considered that the character's turn already started for that combat round, so effects applied to them only start counting off starting from the next round. From a certain point of view, it's actually a consistent behavior. Even though you haven't done anything for that round, you did get to decide to delay your turn. You could think of delaying turn as a "special" move; you have started your turn, you just delay your ability usage.
It certainly seems harsh, but I'd also say that it's an inherent risk of delaying your turn, especially when there are a lot of enemy combatants who haven't moved, and the risk of being cc'd or killed outright is high. It's up to the player to assess that risk.
I'm somewhat on the fence about this. Seems like one of those issues which I'll just have to get used to, whether they get changed or not.
EDIT: I tested a bit more with positive effects. The same rule applies. If a character delays their turn, then another character applies Enrage on them, the former does get an extra turn of Enrage. It only wears off after that character has finished their turn in the next round. So it seems fair, doesn't it - all buffs applied to that character also get extended by one turn.
Last edited by Try2Handing; 23/09/18 09:28 PM.