Capture seems to be working correctly and has found the home teleport button.
Things I've tried to fix issue;
Uninstalling alt1 and reinstalling
Closing other programs/browsers
Switching between DirectX/OpenGL/Desktop Capture to no avail
Opening alt1 before/during Fish Flingers
My settings:
https://imgur.com/rrH6kEV
https://imgur.com/WUDhw35