Hey there,
It seems that when I switched back to Joomla default template, protostar, the issue no longer persists.
https://take.ms/LCnmq
When I changed back to your current template, the issue occurs back.
https://take.ms/09WlZK
Currently, I am not sure what is the cause of it by your current template and perhaps it would be best that you can consult with your current template provider regarding this and see how it goes.