Oh wow, that's good to know, thanks. I use MultiCharts... I'll double check next time I'm testing to see if the same thing happens and update here.

I find it incredible how many small, hidden things there are like this that can easily catch you out. Part of the challenge I guess!

Very true---speaking of small things, I guess there would be no point in even having data2 on daily if you are just going to reference a distant intraday bar (like [390])---may as well keep it lean and just run the single data series.