The newish "Black Cat Weekly" epubs from
https://bcmystery.com/ make my Kobo (Aura One, latest software) reboot.
Other stuff I've had from them has never done this that I recall. And opening epubs from elsewhere hasn't done this for years. (The version it originally came with did it a lot back in 2017 (?)).
I ran all my issues of BCW through kepubify and those versions open instantly.
Has anyone else run into problems like this?
If this keeps up I guess I'll use kepubify on all future issues. I have written to bcmmystery to tell them something seems different about these files.