Confirmed - the marker itself should not be set up with quotes (e.g. call the marker OPFOR1), but when entering the marker name in the dynamic spawn module, quotes are needed to make it work ("OPFOR1"). Thanks GreigPil!

I've uploaded an .rpt file that shows the problem. Looks like a script error. Steps followed to create this:

1. Open mission editor

2. Create new marker at Agia Marina
   • Ellipse
   • 200m x 200m
   • Color: RED
   • Name: Mkr1

3. Add module: Skirmish - Init

4. Add module: Skirmish - Dynamic Spawn
   • Marker: Mkr1
   • Hide Marker: No
   • Faction: Iran
   • Class: Infantry
   • Condition: true
   • Debugs: None

5. Remove "group" line linking Init module to Dynamic Spawn module

6. Add "synchronize" line from Dynamic Spawn module to Init module

7. Place BLUFOR rifleman unit on the map (all parameters default including control: player)

8. Preview mission. Screen will be black (except for watermarks and menus) and no sound is heard.

I am running into the same issue, though I think it is actually NOT a crash (so no crash logs to upload). What happens is once the dynamic spawn module is added to a mission, in preview and in multiplayer I just get a black screen and no sound. Menus are active though, and the Arma 3 watermark appears on the lower right corner of the screen. In multiplayer, other players are even able to see and hear the results of my control inputs (walking around, shooting, etc.). The problem goes away as soon as the dynamic spawn module is removed from the mission.

I will upload my dxdiag.txt in case it helps.