the music of silence

My system has developed a problem with punching-in using VST instruments in that it leaves a silence between the original recording and the punched-in part. It does this either by missing the beginning of the new recording even though it is sounding when I am playing the part, or it records faithfully but cuts off the end of the original recorded part, either way creating a silent gap in the music. I have punched-in successfully before with VST instruments until about a week ago when I used the repeat function to expand a drum pattern by 150 times, after which problems seem to have arisen. I have tried punch-in both via the transport bar and using a pedal via the Nektar Panorama P1 and the same problem occurs. Can anyone think why this might be please? Thanks in advance :cry: :angry: :confused: :open_mouth: :astonished: :frowning: