0 factorial after clicking sign change gives Invalid input

[allamassal]

Describe the bug

When performing a calculation resulting in 0, then clicking the sign change button, and then clicking the factorial button, the "Invalid input" error appears, even though 0! is well-defined. The issue also occurs if multiplying 0 by any number (which leaves it unchanged) after clicking the sign change button, then clicking the factorial button. This only occurs if 0 is the result of a previous calculation (when simply starting with 0 and then clicking +/-, 0 factorial will give 1 as expected).
Edit: The issue also occurs when simply multiplying 0 by a negative number, then clicking n!.

Steps To Reproduce

1. Perform a calculation that gives 0 (such as 1 - 1)
2. Click the +/- button
3. Click n!
4. Invalid input

Expected behavior

The result would be 1, as 0! = 1.

Screenshots

Device and Application Information

• OS Build: Windows 10 Home build 19045.4529
• Architecture: 64-bit
• Application Version: 11.2405.2.0
• Region: en-US
• Dev Version Installed: None

Additional context

Requested Assignment

I'm just reporting this problem. I don't want to fix it.