Games keep disappearing from Ready to Install

Unfortunately the games disappear from both Install and Ready to Install lists

Unfortunately even your order history wont show you the games you have claimed via games with gold.

I keep a spreadsheet of everything I purchase and use a third party site to also keep track of my game collection.

Games disappear from the ready to install when they are delisted or randomly.

You could also try a power cycle of the console. Hold the power button on the console for 10 seconds until it shuts down to see if that helps anything.

Try checking the Xbox Store. If the games have been removed from the "Ready to Install" list, you should still be able to install them from the store app.

This may not be the same situation as yours but games in my ready to install list disappear sometimes. Other times games that are already installed will show up as ready to install. I just ignore it and the problem fixes itself.