Slicing in custom indicator on a different custom indicator gives empty array

Escape

The code below is where the issue is (I think). My slice is returning an empty array, when I would assume it should be returning the specified array length.

note: period is 1500 bars in the case.

class CustomIndicator(bt.Indicator):

    def __init__(self):
        self.addminperiod(self.p.period)
        self.ac_data_zero = bt.ind.Accum(self.datas[0])
        self.ac_data_one = bt.ind.Accum(self.datas[1])

    def next(self):

        time, day = self.get_datetime()
        last_element = last_element_2 = None
        if time.hour % 8 == 0 and time.minute == 0 and time.second == 0:
            self.get_data()
            # do stuff here unrelated

    def get_data(self):
        if self.p.ma_filter:
            d1 = self.ac_data_zero.get(size=100)
            # this gives an empty array
            d2 = self.ac_data_zero[-1]
            # this gives a float value back
            d1 = self.ac_data_one.get(size=100)
            # this gives an empty array
            d2 = self.ac_data_one[-1]
            # this gives a float value back

data 0 and data 1 are given through this custom indicator

class NormalizedReturn(bt.Indicator):
    plotinfo = dict(plot=True)
    params = (('period', 1), ('ma_filter', False))

    alias = ('Return', 'NormalizedReturn',)
    lines = ('_return',)
    plotlines = dict(VWAP=dict(alpha=1, linestyle='-', linewidth=2.0))

    def __init__(self):
        # Before super to ensure mixins (right-hand side in subclassing)
        # can see the assignment operation and operate on the line
        self.addminperiod(2)  # when to deliver values
        if self.p.ma_filter:
            close = self.datas[0]
            close_last_bar = self.datas[0](-1)
        else:
            close = self.datas[0].close
            close_last_bar = self.datas[0].close(-1)
        norm_return = (close - close_last_bar)/close_last_bar
        self.lines._return = norm_return

I feel like missing something basic, but sometimes brain no work well.

Any help would be greatly appreciated.

Thanks!