Forge version: 14.23.3.2678
Twilight Forest version: 3.7.424

There are two issues involving the Goblin Knight Stronghold.

First, if the player is to skip the Labyrinth and Hydra Lair, and go straight to the Goblin Knight Stronghold first, attempting to unlock it has some unusual effects. For one, even if a boss like the Naga has been slain and used for the Trophy Pedestal, you will receive the advancement for unlocking the Stronghold, but the shields will not disappear, mentioning that the player is ineligible to continue. It is still possible to break into the Stronghold.

Second, and I'm not sure if it had been rectified in earlier versions, but the "ineligible" message is unlocalised. It will instead display as twilightforest.trophy_pedestal.ineligible.

Fixed in ae81e3d. Forgot to give the PR the correct keyword to close this.