I get to the entrance of his mansion, and see a sigil. I step onto the sigil. No dungeon warning. Okay. Instance dungeon, then. Should be easy.
Finally, after five battles I have won.
Five battles? In an instance dungeon? That took me 45 minutes to complete. Where was the warning?
Actually, you don't really fight Governor Nakamura in the Governor's Compound during "Death and Taxes". You defeat his best champions, the dungeon's 2 bosses, No Wei & No Hao. After you defeat the two champions, he cowers & surrenders to you & lets you take the gold to give to the villagers at Yagizawa Village. Surprised that we don't get to fight him after every battle we've been through in that dungeon.
That dungeon's entry warning needs to be revised after it got longer. They really made it so it wouldn't be too easy to find Governor Nakamura & the gold in his own stronghold, & I liked it.
The amounts of battles in major dungeons are differed, whilst minor dungeons have only one battle & no instance quests.
It is probably disabled in your options book. You can enable it again in the gameplay section of options.
That was the first thing I checked afterward. Nope. P101 apparently doesn't consider it a dungeon.
I would think that any sigil that gets reset after 30 minutes but takes over 30 minutes to fight should have a warning. Should not matter whether there is a super heavy boss. Time is the important factor.