Before posting, and to avoid disappointment, please read the following:
This forum is not for 2BrightSparks to provide technical support. It's primarily for users to help other users. Do not expect 2BrightSparks to answer any question posted to this forum.
If you find a bug in any of our software, please submit a support ticket. It does not matter if you are using our freeware, a beta version or you haven't yet purchased the software. We want to know about any and all bugs so we can fix them as soon as possible. We usually need more information and details from you to reproduce bugs and that is better done via a support ticket and not this forum.
If you are entitled to technical support then please submit a support ticket. Please do not post the same question to the forum and also via a support ticket. Once again, 2BrightSparks does not provide technical support via this forum.
Using %DATE% & %TIME% will produce results that are formatted as per your Windows short date & long time formats (but with any path/name-illegal characters such as \ / : substituted by dashes, e.g backup 23-10-2018 11-42-31.zip). You cannot change the formatting of those Variables without changing the underlying formats globally in Windows.
The commercial SB versions have many date-part variables such as %YEAR%, %MONTH% %DAY% with which you can build your own format (e.g. YYYY-MM-DD) but these are not supported in the freeware version. There is a list of supported Variables in the Help (Help > Search > "variables" > top hit) and the freeware Help has an extra list of those variables which are only supported by a commercial version: there is a jump link to this freeware exclusion list in para-2 of the freeware Help on Variables