I resized a FAT filesystem. Then the filesystem stopped working as a Windows 10 Recovery Drive. ("This may be due to a recent change in your hardware or software..."). And a running Windows is unable to open the filesystem, when it could before.
Resize tool: gparted-0.27.0-1.fc25.x86_64 (Fedora 25)
The resize was performed on a disk image file, copied from a USB drive as a backup.
gparted was run on a loop device created from the image file using
losetup -f -P. (Or later, Gnome Disks and "Attach Disk Image" from the... whatever you call the app-specific menu, in the top bar of gnome shell).