why the gap of some gapping stocks is not shown on the intraday charts. i.e. symbol PAYC ,09/26/18: the daily chart shows the gap but not the 5,15, and 60 minutes charts

You would really need to contact technical support to know for sure, but the general reason is that the gap didn't yet exist while the first 1-minute bar of the trading day was forming. If there aren't any trades during the 1st minute of the trading day, that first 1-minute bar is just going to be a flat bar using the close of the previous trading day. Then the other intraday time frames get formed from the 1-minute bars making it so the intraday time frames don't have an opening gap.