I used the default F43 Workstation Web-UI ISO within a QEMU/KVM (VM with UEFI!). Once the web-ui installation started, I set the language to Eng/US but changed the keyboard subsequently to German. I had setup partitions in advance ("/" and "/home" are on an encrypted LVM) and thus have unlocked the existing LUKS with the LVM within anaconda and then I have chosen to set the mount points myself: in this context I have created the attached video, which I think is more expressive than a sophisticated elaboration.

A short elaboration of the steps that happen in the video:

1) As you can see in the video, I have set all mount points to be NOT formatted. When I click "next", the next screen confirms that only mounts are set but no formattings.
2) when I go back, anaconda has changed the setting "Reformat" to YES on "/"
3) when I remove the "Reformat" setting once again and go ahead, the outcome is the same again on the next page: no reformatting, only mounts
4) I go back again, anaconda has set "Reformat" again to YES
5) When I leave "Reformat" of "/" on YES and go "next" again, the next screen still confirms that there is no formatting set but only mounts: therefore, this is only a graphical bug -> it only shows that it has set "Reformat" of "/" to YES but it does not really do it
6) Done the same again to show it remains reproducible
7) Then I went "back" again and removed the "Reformat" YES again but then set it immediately again to YES myself
8) Once the Reformat was set manually by me to NO and then YES again (which means the actual YES is set by me and not by the bug), the "next" shows that anaconda now considers "/" to be formatted

Obviously, this is a minor bug and even if it looked serious at first glance (like formatting something that is not intended to be formatted), it is just a graphical bug that does not cause what it looks like.

I found that out during the tests of BZ#2442353.

Reproducible: Always

Steps to Reproduce:
1. KVM/QEMU with UEFI. Several OS pre-installed (the environment is more detailed elaborated in BZ#2442353; final test environment). "/" and "/home/" (all ext4) is in a dm-crypt-encrypted LVM as ext4, there is a separated /boot for each OS (ext4) but a common /boot/efi. All devices are pre-formatted by default means (default luks, default ext4, etc).
2. Default F43 Workstation web-ui ISO from getfedora
3. See text
Actual Results:
Anaconda sets the button of "reformat" to YES in one situation but does not "implement" the YES

Expected Results:
Anaconda should leave the button always the way the user set it

Additional Information:
x86_64. F43 KDE Spin host. Let me know if you have questions