Undersized Party Bug

Hello, I have now bumped into this problem at least twice in the last day. It's very simple, and I've never seen this occur before Shadowbringers at least. So what happens is I tick undersized duty so that I can go into a solo instance for Shiva Extreme and then...it forms an 8-man party instead of a solo instance. It only does it once and goes back to normal after I withdraw.

Date & Time: 3/7/2019 15:08
Frequency: Happened twice now
World name: Louisoix
Character name: Enra Acana
Class/Level: 80 Scholar
Party or solo: Solo
In-game time: 14:08
Area and coordinates: It has happened in several places now. Housing district in Mist, out randomly in the wild. Cannot pin to one place.
Steps:
1. Tick undersized party setting
2. Join a duty
3. 8-man party forms instead of solo instance



-=-=-=-=-=-=- System Information -=-=-=-=-=-=-

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SYSTEM_STORAGE D:\ SYSTEM_HARDDISK_DRIVE SYSTEM_TOTALDISC_SPACE 930.446GB SYSTEM_FREEDISC_SPACE 751.480GB
SYSTEM_STORAGE E:\ SYSTEM_HARDDISK_DRIVE SYSTEM_TOTALDISC_SPACE 931.496GB SYSTEM_FREEDISC_SPACE 307.480GB
SYSTEM_DIRECTX_VERSION DirectX 12
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SYSTEM_GRAPHICS_DEVICE \\.\DISPLAY1
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SYSTEM_GRAPHICS_DRIVER C:\WINDOWS\System32\DriverStore\FileRepository\nv_dispi.inf_amd64_7a8e74171e1b8492\nvldumdx.dll,C:\WINDOWS\System32\DriverStore\FileRepository\nv_dispi.inf_amd64_7a8e74171e1b8492\nvldumdx.dll,C:\WINDOWS\System32\DriverStore\FileRepository\nv_dispi.inf_amd64_7a8e74171e1b8492\nvldumdx.dll,C:\WINDOWS\System32\DriverStore\FileRepository\nv_dispi.inf_amd64_7a8e74171e1b8492\nvldumdx.dll
SYSTEM_GRAPHICS_DRIVER_VERSION 25.21.0014.1935
SYSTEM_GRAPHICS_DRIVER_DATE 3/1/2019 01:00:00
SYSTEM_GRAPHICS_DRIVER_LANGUAGE English
3.0
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SYSTEM_GRAPHICS_VERTEX_TEXTURE SYSTEM_SUPPORT
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SYSTEM_SOUND_DRIVER_DATE 4/11/2018 00:00:00
SYSTEM_SOUND Realtek Digital Output (Realtek High Definition Audio)
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SYSTEM_SOUND_DRIVER_LANGUAGE English
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SYSTEM_SOUND Speakers (Realtek High Definition Audio)
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SYSTEM_INPUT {6F1D2B61-D5A0-11CF-BFC7444553540000}
SYSTEM_INPUT_NAME Keyboard
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SYSTEM_INPUT {A9814A90-5790-11E8-8001444553540000}
SYSTEM_INPUT_NAME USB Keyboard
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SYSTEM_INPUT {A982D130-5790-11E8-8002444553540000}
SYSTEM_INPUT_NAME USB Keyboard
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SYSTEM_INPUT {B0E2DD10-E739-11E8-8001444553540000}
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SYSTEM_INPUT {B0E35240-E739-11E8-8002444553540000}
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SYSTEM_INPUT {B0E37950-E739-11E8-8003444553540000}
SYSTEM_INPUT_NAME Razer Basilisk
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SYSTEM_INPUT {B0E3C770-E739-11E8-8004444553540000}
SYSTEM_INPUT_NAME Razer Basilisk
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