iPhone 17 Pro Max videos in gallery have blue and light green grid stripes

If you are seeing fine grid lines or a visible mesh pattern in a photo/video on your phone, the image was most likely either captured using a third-party camera app or is being viewed through a third-party app that is altering or processing the image.

The native Camera and Photos apps generally do not add such fine grid patterns to the actual photograph. If the lines appear only when the image is opened in a particular third-party app, they may be the result of that app’s display rendering, image processing, compression, sharpening, or scaling.

A useful way to identify the source is to open the same photo in the native Photos app. If the grid lines disappear there, the problem is most likely with the third-party app rather than the photograph itself. If the lines remain in Photos, then they are likely embedded in the image or were introduced during capture or editing.

So, in simple terms: fine grid lines are not normally a characteristic of a photo taken or displayed by the standard Camera and Photos apps. Their presence usually points toward third-party capture, processing, editing, or display rendering.

I have resolved the issue on my iphone 17 , just go do the hard restart to phone. It will be removed, first press volume up once , volume down once , and then hold the power button for 5-10sec till you see the apple logo , then release it , automatically restart the phone and problem resolved

Have you tried importing the file again? Have you tried a minor edit so the file re-renders?

This discussion thread may help you --> Grid lines in 18 pro max - Apple Community

These aren’t third‑party programs; it’s in the Photos app itself. I transferred the data from my iPhone 13, and all my videos have this issue with stripes.

Same for Iphone 17