I found that in coming coaxial cable into my house has about .5 ac amps on line. I had to put a filter on the line to put it at zero. But my speeds are fine and snr is good. But playing games not so much. Once I put the filter on it definitely is better but not that great. So is it normal for ac current on in coming line? I tested this all with a clamp on meter specifically made for this. All my signal levels is good and snr is good. But definitely seems like emi.
No. There should not be any stray voltage on the line. You should get a tech out to investigate the lines / grounding. You may need an electrician out to investigate your residence's electrical system / neutral. YMMV. Good luck !