Aafter I hit the Record button to loop the progression I just played on my guitar, the playback has a dead spot in it. Meaning,

it's as though the amp stops recording for a split second after I hit Record and there's a dead spot. So the playback is not seamless.

There's always this blank spot before the loop function kicks in.

The weird thing is I don't have this problem if I loop one of the song or drum tracks.

Anybody have any ideas what's wrong and how to fix? Thanks.