Problem with plotting TGraphErrors with ErrorBands

I am facing a very strange problem and I would appreciate your help.
I am trying to plot two TGraphErrors on the same canvas, I tried it with multigraph with Draw(“A3LP”); option and also I tried something like:
However, I keep getting very strange, large, out of range lines, that are not error points, since I checked and errors are reasonable (very small).
I assume that I am doing something wrong with drawing option, could you give me any tips what should I use instead of the mentioned above ones?

P.S. these lines sometimes also change when I for example, put a legend in a different position. Very weird.

Anyway, thanks in advance for your help! I hope to hear from you soon:)

Can you provide an example reproducing your problem ?