Why doesn't it ask for a password when re-signing a document?

Question

Windows

Good afternoon, I did not find a description on the Internet, why is the password not requested again when signing MS Office documents?
for example, signed 1 file by typing a password, opened the second file without closing the first, signed the second file without a password.
it is clear that the password is stored in memory, but why so? Is there an explanation from MC on the Internet?
as in the photo:

Answer 1

What do you sign? And are you sure that when you sign again, the second signature really appears? How long does it take between attempts?