Well,

If its Comcast POTS service its an EMTA and not VOIP. It's a different tech. The EMTA could be causing it, bad crimp on a stranded core end rather than a solid core one. Wet, corroded...all kinds of bad. The CO card COULD be bad but bleed isn't usually something we see unless its been damaged by water etc... The hydra cable plugged into it also could be compromised. This is telecom 101 trouble shooting for any tech in the field.