IndexError exception when Bytes condition is used

[MariaRigaki]

When using a condition such as the following:

Malicious, C&C-FileDownload:
    - dstIP=104.248.160.24 & Bytes>0

I get the following exception:

Problem in main() function at load_conditions 
<class 'IndexError'>
('list index out of range',)
list index out of range

If the Bytes>0 condition is replaced with another such as State=S0 there is no exception happening.