Will a glass of wine every once in awhile hurt me while on Epclusa treatment?

There is no interaction between alcohol and Epclusa (antiviral combinations) you are on, then one would think it is ok to drink let us say one glass of wine 3 times a week, sounds ok.
But if you think about it, Hepatitis C (HCV) over the years ( you do not mention how long you have had this condition) damages the liver and can cause irreparable damage, it can cause cirrhosis, I am sure you are aware of this and at the same time alcohol is metabolized mostly by the liver and there is no secure amount of alcohol that may potentially cause liver damage and of course, everyone reacts in different ways to alcohol depending on quite a few factors, age, gender, amount of alcohol ingested, frequency, etc..

Then, as I am not a Dr., if I were you I would definitely consider speaking to your Dr. about how safe it is to drink whatever it is you would like to drink, how much, how frequent, etc..

Then I found the following:

Because alcohol promotes the progression of severe fibrosis to cirrhosis with severe and often fatal end-stage liver disease, the National Institute of Health Consensus Conference (1997) has stated that "more than one drink per day is strongly discouraged in patients with hepatitis C, and abstinence from alcohol is recommended."

Source: National Institute on Alcohol Abuse and Alcoholism

Now, I am not implying at all that you have a problem with alcohol nor judging you in any way if you drink or not, you asked a question and as I am here to try and help people, this is all I am doing, trying to help you.

One more aspect of it all, I can recommend, research, analyze, and give you an answer but at the end of the day, it is your life and the choices are yours to make, your decisions and consequences.