In other words, maybe you are getting something incompatible with your equipment. This is only a really wild guess. I can her my neighbors power equipment in a house beside me on my telephone. Pat Personally, re-recording makes me nervous because of the loss of quality in the dictation. In spite of your own good equipment, you're at the mercy of the phone company and mother nature.
Bad weather can affect transmission across phone lines.
For one of my home offices I had the phone company out three times before they finally replaced my outside line with copper wire, which helped a lot. So give your phone company a call. They might be the answer.