Thank you for contacting Syncfusion support.
Based on the given details, we have loaded the Accordion control in StackLayout and the StackLayout also holds the buttons above and below the Accordion control to replicate the reported issues i.e., when the accordion item is being collapsed (other child elements of StackLayout gets updated earlier than collapsing the item) and when the accordion item is being expanded (flickering of child elements at the bottom of the view) in our sample. We have also defined the back ground color to both stack layout and accordion control as mentioned.
But unfortunately, we are unable to replicate the issue at any of our public Nuget release version i.e., v184.108.40.206 – beta, v220.127.116.11, v18.104.22.168, v22.214.171.124, v126.96.36.199, v188.8.131.52 and v184.108.40.206. So, we suggest you to please check with the below attached sample, if possible please modify the below sample to replicate the issue and revert us with some additional details like Xamarin.Forms version, SfAccordion version, share the XAML page where the Accordion control is loaded and its related pages or view or video link which would highly help us to analyze the issue better and update you an appropriate solution.
Dinesh Babu Yadav