Blocks Inserting Upside Down

I have a file where every block inserted is upside down. This includes blocks created in the file and blocks copied into the file. I am wondering if I flicked some setting somewhere to cause this.

It looks like it is a specific file. I have uploaded it to the support site.

Copy a block to the file.
Delete the block
Insert the block (it’s upside down)

Insert one of the existing blocks (with the CPLANE World Top). Its upside down.

Thanks, I replied from the tech support email. The issue was that your Cplane in the file was rotated 180 degrees around the X axis, resetting the file’s Cplane to World Top in Perspective solves the issue.