WordPress 6.4.1 and Cwicly 184.108.40.206.
If you create a new custom template that applies to your pages, it works everywhere except in the Site Editor.
The Site Editor is the only place to show it using the Index template:
This only happens with WP 6.4 I believe.
Thank you for bringing this to our attention.
And thank you for the screencast, it helps!
I have been able to reproduce this issue on my end, and can confirm it is a bug.
We’ll have to investigate further, to see whether this might come from WordPress changing the template info retrieval on the Site Editor.
Apologies for the inconvenience.