Ext4 formatted flash drives lose files when the drive is removed from the PC on 19.04

I’m using PopOS 19.04, although the issue was also present on vanilla Ubuntu 19.04 and caused me to lose some important files.

Whenever I use a flash drive for Linux, format it as ext4, add files, and then remove the drive from the USB port, all of the files disappear. The only way that I have recently found to make them not disappear is to right click and hit “remove safely”. I can do this every time if I have to but I don’t have to do it for Windows, what is different? Is it just a bug?