I think there is a bug with Pro 2.4 with the Export Raster tool. I've attached two videos to illustrate what is happening but I'll explain. When you use the export raster tool (right-click raster -> Data -> Export Raster) and check the box for "Force RGB" under Renderer Settings instead of the output being in RGB it is stretched.
However, when you check the box "Use Renderer" under Renderer Settings the output is in RGB. They are doing the opposite of what they should. Like I said, unless I'm completely misunderstanding this, this is a bug. I have reported it but the bug reporting site just doesn't seem like I can go to as in depth as this so maybe someone can pass this along with an elevated priority. I also don't know if they are looking into it because I haven't received any kind of follow-up. If I'm misunderstanding can someone please explain.
First video is me using the "Force RGB" setting and the second video is me using the "Use Renderer" setting. Just play them through. the Use Renderer video is a little longer because it seemed to take more time processing. Thank you!