"Bug" in Debian Installer?

[Andrew Wood]

Ive just used the Debian 11 installer ISO running from a USB stick to do 
an install (AMD64/UEFI) on another USB stick to use as a 'portable PC'.

When it got to the Grub install stage I was expecting it to ask me which 
disk I wanted Grub installed on as it has in the past but instead it did 
not.

When I came to reboot the PC I found not only had it put Grub on the USB 
it had also put on the PCs NVMe SSD overwriting the Windows bootloader 
on there.

Surely it should have prompted which disk I wanted it on? I thought it 
was only Windows that trashed other peoples bootloaders ;)

Regards

Andrew