Hey Zâsh,
I’m not seeing any known bug with Soul leech, however if the issue persists, please do report it to our developers, and they’ll be able to check this out for you. 
Feel free to provide this information in your report, this may be very useful to them.
Bug fixes are usually published in our Hotfix blogs and patch updates, which can be found in the News section of the main site.
Thank you!