Hi Davi Fabiano,
We checked the reported query "SfListView.GroupHeaderTemplate - button icon does not appear in the first group", and we are able to reproduce the issue at our end. we have logged the bug report at our source and working on it. We will fix the issue and include the fix in our Weekly Nuget Release, which is planned to roll out on July 5, 2023. We will appreciate your patience until then.
You can track the status of this report through the following feedback link,
https://www.syncfusion.com/feedback/44447/icon-in-the-groupheadertemplate-is-not-visible-for-the-first-group-header
Note: The feedback link provided is private, you need to log in to view this feedback.
Regards,
Suthi Yuvaraj.