python - TA-Lib producing NaN's for large inputs (length 1100+)

Question

When using the python TA-Lib library with large arrays (length 2000) I am finding a TA-Lib function (for example BBands) only produces results up til index 1100 then the rest of the result is NaN's.

So for a array of 2000 passed to BBands the final 900 values are NaN's.

I am finding this result consistent across all functions I have tried.

Is anyone else experiencing this issue?