Creating Other Timeframe Overlay // issues with high timeframe with high bar lookback

[unfinishedtrade]

I'm trying to figure out if there's some settings I need to change. I made a HTF overlay indicator. It works perfect on smaller timeframes and almost anything except when you have a higher timeframe like daily and make it lookback 15 or more bars. In the third picture you can see it's working for about 13 bars then the last 3 are likely returning null and show up at 0. The actual timeframe of the chart is 5m if there's a restriction depending.