this happened on chaos a while back a few weeks on the same castle, and was not on purpose, the game just said nope.
VModCinnamon, I think Ash was saying it happened to Chaos Server once and around 2017.
Based from the conversations, I've read from another social media thread for iRO Thor Server, the bug seemed to be intentionally done by the defending guild - from how the guild members and/or guild alliance members in those conversations reacted, they felt proud, or so much delighted for that bug during the Skidbladnir Clash.
I guess, WoE is a thing in Thor Server. I suggest maybe GM's can stop the increase of economy for Skidbladnir Castle and prevent God Creation for a week, or until this bug has been fixed. To give the opposing alliance the chance to snatch this Castle in the upcoming WoE 2 in a fair play, not in a buggy situation.