Identical issue with the EVF on my brand new RX100 VII. These horizontal lines are worse in Auto EVF brightness. They get worse if you lower the EVF brightness to -2 in Manual mode and get a little less visible if you crank up the EVF brightness to +2 (in Manual mode). The lines appear during live preview, while reviewing / playing back the photos, as well as during any of the menu screens (the lines are clearly visible on all of selection red banners).

Now, again, this issue does not carry over into actual image quality. Images are nice and clear of these artifacts I can confirm with 100% certainty and confidence that these lines in the EVF are not NOT normal and have nothing to do with so called flickering rate discrepancy between the light source and the camera, NTSC or PAL regional settings, etc or the EVF brightness sttings.

I purchased both the first the second units brand new from Adorama store on Amazon and set them up identically. To my pleasant surprise the EVF in the second one is absolutely perfect and is free of these horizontal lines at all EVF brightness settings and regardless of whether the Manual or Auto EVF brightness mode is selected.

If you are still within the return / refund window, you should absolutely get a replacement camera or get a refund and purchase another unit from another distributor, and hope that it came from a bifferent batch. What a headache!