Might be because of the bots? Due to the way I added bots to TDM (and CQ as well, not sure why OBJ mode ends on it's own. Don't recall having bots in that one).
Unlike in proper COOP mode, the server considers them part of the player count (despite the fact they don't show on the player count visible from server browser) and thus the map never enters pre-round. So if there's a round timer set on the server it will always start on those modes even if the server is empty due to the bots still being counted as being counted towards server population.
New players take a look at the download section too. We have a lot of maps created by various people who visit this website that are not included with the mod download. The majority of these maps are designed with deathrace 1 and 2 in mind. We want to know what you like about the maps. The latest mod download already includes a few maps from the download section to give you an idea on what this community has created. In the future we hope to update interstate with content you all want.
I remember a stunt type map with monster trucks and a platform in the sky where stuff spawned. Can't remember the name but it was one of the early ones I think. I haven't checked but if that map isn't included yet I'd love that one