It happened during shooting. I pulled all the shutter blades out and continued shooting.
I'll have to order a new shutter mechanism next + maybe buy a new camera just in case.
My current gear:
Cameras:
Sony A7 Mark III
Lenses:
Tamron 28-75mm f/2.8 Di III RXD (Model A036)
Tamron 35-150mm f/2-2.8 Di III VXD (Model A058S)
Tamron 90mm f/2.8 Di III Macro VXD
Tamron 150-500mm f/5-6.7 Di III VC VXD (model A057)