Doesn't support anchor links it seems:
Encoder https://calendar.google.com/calendar/render#main_7 kF9DKUm9hMdDPUOCFu-QohzySQDx6pLN
Decoder kF9DKUm9hMdDPUOCFu-QohzySQDx6pLN https://calendar.google.com/calendar/renddabD
Encoder https://calendar.google.com/calendar/render#main_7 kF9DKUm9hMdDPUOCFu-QohzySQDx6pLN
Decoder kF9DKUm9hMdDPUOCFu-QohzySQDx6pLN https://calendar.google.com/calendar/renddabD
I'll open an issue.
Thanks for report :)