Removing the last party member from the party does not disband the party. Party status shows a party of one.
Newhaven, Narrow Path
Also here: Ian2.
Obvious exits: north, south, east, west
[HP=26/MA=3]:par
The following people are in your travel party:
Ian (Druid) [M: 16%] [H: 61%] - Frontrank
Ian2 (Bard) [M:100%] [H: 85%] - Frontrank
[HP=26/MA=3]:uninvite ian2
Ian2 has been removed from your followers.
[HP=26/MA=3]:par
The following people are in your travel party:
Ian (Druid) [M: 16%] [H: 61%] - Frontrank
[HP=26/MA=3]:disband party
[HP=26/MA=3]:par
You are not in a party at the present time.
Ian (Druid) [M: 16%] [H: 61%] - Frontrank
From Regmud:
[HP=560/560,KAI=56/56]: (Resting) par
You are not in a party at the present time.
Gardner Denver (Mystic) [K:100%] [H:100%] R - Midrank
So the only real difference is regmud shows you at midrank, GM shows you still in the frontrank. Is this really a bug?