"click" noise when using silence function on editor

During today have realized that when I use the function “silence” in the audio editor of an audio track (i.e. to silence a part of a guitar track) I can hear a click noise at the point where the audio is silenced. I have been using this function lots of times and have never had this issue until today. I have not changed my audio interface. I have tried to restart the computer and nothing has changed.
Any ideas please?

Thank you very much,