Problems sharing files with users outside Tenant

An additional Sign In window appears for external users with whom we share files or folders through OneDrive and/or SharePoint. The window for entering the email appears (to validate that it's the intended recipient), but before entering the verification code, the Organization Sign In window appears. This sometimes requests a password, which can cause issues or even prevent users from sharing these folders with external users.

Authentication flow example:

Normally, step 2 is followed by step 4, but in my case, it's taking me to step 3 where I have to re-enter the email address I'd already entered in step 2. This isn't normal. In this case, there's no major problem with this email because it then asks for the verification code, and I log in without a problem. But for example, when I tried another email address, also from Gmail, it asks for a password to authenticate:

Then I realized it's asking for my password because that email is associated with my GitHub account, and it's trying to authenticate with a password. However, this flow is incorrect because for authentication to SharePoint files shared with external users of the Tenant, it should only ask for the username and verification code. The fact that it asks me to enter my email twice, as in step 3 of each example, and that it occasionally asks me for a password, is incorrect in the flow, and I don't know how to change that.