Drupal is using a configured timezone which could not match with the user's timezone. While it is natural, can confuse the user in case the scheduled hour appears somewhere else (i.e. in a view).
Solution
Add a label as disclaimer on the widget to clarify that the time is a local time and potentially could not match with the Drupal configured timezone.
Needs work
1.0
Documentation
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It's likely this issue predates Contrib.social: some issue and comment data are missing.
This needs some work to tackle how much work would be using the current timezone and test cases for that. If it's too complicated and needs a full rewrite on the JS part, we will need to document that the module does not support this right now.