Thanks, Xophious. I hope this helps.

Platform: Windows 7, 64-bit.
ISP: TPG (Australia)
Type of Internet Connection: ADSL2+
Internet Connection Speed: Download typically at up to 6.5Mbps, Upload at up to 750kbps.
Date & Time: 19th April, between about 00:00 & 03:00 Australian Eastern Standard Time (or 18th 7-10am PST)
Frequency: About every 20 minutes to half hour
Character Name: Thal Icebound
Race: Midland Hyur Male
World: Figaro
Class/Skill Rank: Thaumaturge, Rank 28 at the time
Physical Level: 48
Area and Coordinates: Nanawa mines, 5/5 to 6/6 to 8/5
Party or Solo: Party with one other character, "Zero Experience" also male midlander
NPC Name: N/A
Monster Name: Various
In-Game Time: Various
Steps:
1. Separation of characters through forced return to aetherial gate after defeat.
2. Characters move back within range of each other.
3. One or more party members does not appear to recognize their party member's presence as outlined in the original post.