Goblin Army fails to spawn

[Nixitur]

tModLoader version

version: v0.10.1.1

Tremor version

version: 1.3.2.7

Description

I use the Goblin Battle Standard and hear the "boss spawn" sound effect. The Battle Standard vanishes, as it should. However, there is no "Goblin Army is approaching from the [direction]" prompt and the Goblin Army never actually spawns.
Despite this, the world is now locked into "Goblin Army approaching" mode, so you are unable to use another Goblin Battle Standard. I'm pretty sure it won't spawn naturally either.

Expected behavior

I should be seeing a "Goblin Army is approaching" prompt and the Goblin Army should arrive at some time.

Steps to Reproduce

1. Use a Goblin Battle Standard.
2. That's literally it.

Mods

The character I use is vanilla, so without mods.
I have generated a fresh map, using only Tremor.
I am testing the Goblin Battle Standard with only Tremor active.

Additional Information

Whether the map or character was generated with Tremor seems to be of no import, only whether Tremor is currently active.
Visiting a bugged map (as in, locked into "Goblin Army approaching" mode without having gotten the prompt and without it actually approaching) with Tremor temporarily deactivated immediately makes the prompt appear and the Goblin Army quickly arrives.