I do hope you're well, safe and having a wonderful week.
Thank you for contacting us. I am sorry you're experiencing problems with Vizlib Sankey Chart.
Based on the image provided, it looks like you're currently using Viztips. I'm guessing a Sankey chart inside the KPI.
To remove them on hover, I recommend turning it off or switching to Static Viztips.
I believe I have provided a solution for the ticket you have raised with us. However, if the resolution provided is not to your complete satisfaction, please reply to this email.
Please note your unique ticket reference (#34906) and URL https://community.vizlib.com/helpdesk/tickets/34906
Technical Support Engineer