Reposted from Game Support forum per moderator request:
The Island reward chests that I received are unable to be opened. I get either a “You cannot interact with this object” or “Your inventory is full”. My inventory is not full.
When I click on the chest, the window it brings up is named “Normal Chest” with 0 rewards.
All the chests you get from Twilight Isle are broken. Splendid Destruction Stone Chest, Splendid Life Shard Chest (M), Splendid Guardian Stone Chest, Lavish Life Leapstone Chest
First screenshot is how working chest looks like and the second one is how the broken chest looks like. As you can see working chest shows whats inside the broken one does not.
Looking at the descriptions of the contained items it appears these chests were accidentally coded to drop Tier 2 materials. That would explain why they aren’t working correctly.