I had an event today on my server and the location announced was G18 and the two maps (in game and RustIO) both said I was in G19 and G21 respectively.  I even made sure I moved to the outer edge of the zone dome before I checked.

Yeah. Having this issue too

Seems the calculation needs updated again. Thanks for reporting.

I am not sure if you have seen the thread regarding the chest being spawned in Blacklisted areas, but it is happening a lot, I have all monuments blacklisted (because of bot guards) as well as the outpost/bandit camp, but still get the occassional spawn right in the middles of them,
I just checked the /dtd help chat cmd and found that there are many monuments missing from the list including bandit camp, docks (2), Airfield and outpost ?,

yes i have. I also copied the syntax of the monument names shown in /dtd help