With the Minimal scene it’s all ok using my skybox
by user 241452911240937472
Do you maybe have another camera in the scene that is also set to main camera and has different clearflags ?
You can search with t:Camera in unity
That’s the first thing i do this morning, the only thing that seem to fix the issue, is to disable the “Diplopie To Camera” component attached to the Camera created by Needle on automatic setup
by user 241452911240937472
what is diplopie to camera?
Looks like it adds some other script or something, could you make a screenshot of that component?
Perhaps click on it and see from what folder it comes from?
Can you change the Background alpha color to 1 ?
After checking it seem it’s one of my colleague who developed this one, the whole issue seem related to this script 
by user 241452911240937472
Ah, ok - so you were able to solve it now? Thanks for letting us know!