Create or Update Remote Record Action Uniqueness checkbox cannot be checked during subflow creation.

[html5lv2stu]

I am developing a subflow to create records on other instances using the Create or Update Remote Record Action.
However, when I click to check the "Determines uniqueness" box next to where I want to specify Fields, it is not checked.
I was able to check the box for actions that create or update records in my instance.
Why can't I check the box in the Create or Update Remote Record Action?

[GlideFather]

Is it okay or no? 😛 if no, please share screenshot, I don't get the issue :))))