If the filter wildcard is not the first character, the “Publish artifacts to S3 Bucket” step will drop all characters before the wildcard. e.g. if the filter is ‘package.*.nupkg’ the file ‘package.2.7.0.4.nupkg’ will be uploaded as ‘2.7.0.4.nupkg’
The culprit seems to be explicit code in FileHelper.getSearchPathLength(), but the behavior is not obvious when configuring the step and there is no way to configure around this if you need to match like this.

In my case to workaround this, my script moved the package.*.nupkg to an isolated directory and publish from there.