So I did some more experimenting with this and I've noticed that it has nothing to do with the inventory slots, chests, or the recipe book. It's actually a dead spot for the mouse cursor on the screen. The reason closing the recipe book or opening a chest "fixes" the problem is because it centers the inventory menu on your screen and moves the slots away from the cursor deadspot. This deadspot also exists on the in game menu, it's just not noticeable because the clickable buttons on the menu are so large.
I have been having this same issue. I've noticed that it is only in effect when I have the crafting recipes open, if I close the recipes the inventory slots become available again. I don't use any mods or overlays.
CPU - FX-8350
Graphics - GTX 1070
Window 10 latest updates 7/6/19
Java version 8 update 211 (build 1.8.0_211-b12)
Minecraft version 1.14.3
I figured it out. It's the stupid Xbox Game Bar for windows 10. When you start a game it flashes a useless tip towards the top right of your screen, this is what becomes the cursor dead spot. You can fix it by opening the Xbox Game Bar in your start menu, click on the gear icon for settings, and un-check the box for "show tips when I start a game".