KFT: Yellow and Blue Goblins not spawning

Description of the bug: (optional screenshot/video): Yellow and Blue Goblins not spawning when offering the appropriate pork and rice wine to their respective spots (lamp and rocks). This breaks the ability to complete certain quests that require defeating the goblins.

What is supposed to happen?: When dropping the correct "Use" item at the correct location (according to HiddenStreet), the yellow or blue goblin should spawn in the Top of Black Mountain map.

Where did you find and/or notice this bug?: When trying to complete the KFT quests and hunting for cards, I was unable to spawn either yellow or blue goblins.

A step-by-step guide to re-producing this bug (optional):

1. Complete the two KFT quests that provide Rice Wine and Roast Pork
2. Go to the Map: "Top of Black Mountain"
3. Drop the Rice Wine in front of the lamp (right of the map)
4. Wait a few seconds to allow a goblin to spawn. Notice that nothing spawns
5. Drop the Roast Pork in front of rocks (right-most of the map)
6. Wait a few seconds to allow a goblin to spawn. Notice that nothing spawns
7. Give up...

Extra information (optional): The green goblin (paste dropped in front of a hollowed tree) does spawn after placing one or more buckwheat pastes; only the blue and yellow do not.

Update (after maintenance 9/3/20): Hasn't been fixed. While monster card hunting, I noticed that the yellow and blue goblins only spawn once but subsequent offerings don't respawn the goblins. Green goblins are unaffected.