Hi Peregrino,
Thank you for using Syncfusion products
We confirmed that reported scenario is a defect from our end. We have logged a bug report for this issue “ShowingAdvancedToolTip event Propeties are not Working” Here we have provided private feedback link, we request you to log in to view the link further.
The fix will be available in our upcoming Volume2 SP1 release which is scheduled to be rolled out at the end of August 2020. Would waiting for the official release is OK for you? Otherwise, we can provide a patch in the reported version v18.1.0.52 on 31st July, 2020. If you have any more specification replication procedure or a scenario to be tested you can add it as a comment in the portal also if the version is not correct, please specify the version in which you need the patch
Regards,
Arulpriya