Why there's a Nubialog and it costed me 17.9GBs?

Hello, so i just found out that my Blackberry Aurora 32GB, 4GB RAM has full storage space. I then deleted many unused junk but then, after a few hours or a few days, the full storage warning popped up again. This repeat so often and then i plugged my phone to my PC and i found out there's a folder called nubialog and inside it there's a folder named btlog and it contains 17.9 GB of files. Can somebody give me a solution? May i delete the files?

Thank you for your attention

The system won't allow you to delete anything crucial, so just delete it. Dunno what it's coming from though.