Line 176 of the current release (3.2.2) reads as follows:
string gridPos = GetGridString(position);

I believe this should be:
string gridPos = GetGridString(playerposition);

In its current form, position is defined on the previous line (175) as a new Vector3 object, causing the reported grid position in chat to always be the center grid square of the map (0,0) instead of the player's grid position who threw the signal.

Making this change on my own server has fixed the grid position being reported in chat.