On my end the fixed background works perfectly fine as well.
I can’t reproduce the bug on my setup but I remember someone fixing this issue on a previous version of chrome by making sure the position of the element having the fixed background is set to static. (yours is on relative).
If doing so change your layout you can still use an extra div to hold the background image.
(parent = section 1, position relative) > (div with background image, position static and you can set width and height to 100% to fit section 1) > rest of you content inside this div.
This way the children elements with absolute positions will look up to the first ancestor without static position (section 1) to evaluate their coordinates and your layout will be the same.
One thing as well is that background fixed property doesn’t work on all mobile browsers but I guess you are using a desktop version so this might no be relevant.
Hope it might resolve the problem. Let me know as it’s not always easy to reproduce this kind of error.