Unity piped as graphics overlay to OBS but particle systems do not show over feed only polygons

Hello guys,

This is a rather niche topic and I cannot really find any info regarding this on the net, So I have a Unity project that runs with solid background color and some lowerthird and on-screen graphics pre-animated with Animators.

I then have a TCP listener in the scene to listen for trigger In/Out animation commands of lowerthird showing information. This is overlaying on my OBS (Open Broadcast Software) feed to be used as live graphics overlay for streaming. All is working fine and the lowerthird is overlaying properly and is being triggered fine but I have found a strange rendering issue, So any 3D ,2D polygon objects used in the scene overlays fine on OBS but when I attempt to make use of a fog or smoke effect using any of the particle systems I find that they do not render in OBS... It's like the polygon objects have a clear key signal to overlay on the video but not the particle systems? How would I go about to force the particle system to render over the OBS feed?

Best regards