Hi,
Sorry, I missed your message.
Anyway, you won't see much on my website because in the meantime I have added an override to correct this.
I have simply changed in file templates/allura/html/layouts/com_easystore/badge.php
$discount_value . '%'
to
number_format((float) $discount_value, 2, '.', '') . '%'
In Easystore 2.1.0, this was ok, because the column in the DB table was only allowing 2 decimals. In 3.0.0, you changed the column to 5 decimals, and as far as you just push the value as it is, it was showing as 10.0000%