Date & Time: 05-Oct-2022
Frequency: very frequently
World name: Sophia
Character name: Luthien Nengelion
Retainer name: N/A
NPC name: N/A
Monster name: N/A
Class/Level: Any & all / 90
Party or solo: Party & solo
In-game time: approx. 1830 GMT+0930
Area and coordinates: N/A
Housing: N/A
Steps:
Please note that this is not the first time I have experienced this issue. It is ongoing and I find it most often occurs whenever I am logged in for 3+ hours at a time. The steps below are simply the situation where the bug occured today:

1. I was in a party with my partner and I sent a map coordinate using the <flag> function. It did not appear for him. Party chat was working perfectly fine just a few minutes prior to this. I had been logged in approximately an hour at that stage.
2. I tested to see if other chat functions were also affected, as they usually are when I experience this issue, and confirmed that /p, /fc, and /tell are all completely non-functional. /s, /y, and /sh are all functional.
3. At the suggestion of several people on the FFXIV Reddit page I submitted a ticket requesting that the GMs review.
4. I experienced a 90006 error about 30 minutes after the problem began and was forced to reload my game, so the problem is currently no longer persisting. However, it is still a problem that I have been dealing with for over a year now, and I know it will continue to be a problem unless something is resolved. Currently, I know that reloading the client will temporarily fix the issue but it is not permanent.

I am not going to include the additional information requested because I am quite certain that none of it is relevant to the issue at hand. I have seen posts on the FFXIV Reddit page where other users were able to have the issue resolved by referring it to a GM in-game and the GM then fixed through their end, however when I did as such, they referred me here instead.