bug: partial tip invalid motion planning error for nozzle A1 -> well 0 of plate in row A

[strangemonad]

Overview

when configured for single channel A1 of 8-channel pipette, can't target the back row of wells.

Steps to reproduce

Here's an example that picks up a single tip with A1 and tries to walk back through the wells of a plate in deck row A

the code won't run directly as is because it uses some of our internal utility wrapper classes but should capture the spirit of the bug.

tip_rack = self.ctx.load_labware(
    config=LabwareConfig(
        name="50_1",
        load_name="opentrons_flex_96_filtertiprack_200ul",
        namespace="opentrons",
        version=1,
        load_location=DeckLocation.B3,
    )
)

plate = self.ctx.load_labware(
    config=LabwareConfig(
        name="plate",
        load_name="nunc_96_wellplate_2000ul_instance",
        namespace="instance",
        version=1,
        load_location=DeckLocation.A2,
    )
)

pipette = self.ctx.get_instrument(config=self.config.pipette_1_config)
pipette.tip_racks = [
    tip_rack
]

pipette.context.configure_nozzle_layout(
    style=protocol_api.SINGLE,
    start="A1",
)

pipette.pick_up_tip(tip_rack.wells()[-1])
pipette.aspirate(Amount(amount=10, unit=UnitOfMeasure.U_L), plate.wells()[7])
pipette.aspirate(Amount(amount=10, unit=UnitOfMeasure.U_L), plate.wells()[6])
pipette.aspirate(Amount(amount=10, unit=UnitOfMeasure.U_L), plate.wells()[5])
pipette.aspirate(Amount(amount=10, unit=UnitOfMeasure.U_L), plate.wells()[4])
pipette.aspirate(Amount(amount=10, unit=UnitOfMeasure.U_L), plate.wells()[3])
pipette.aspirate(Amount(amount=10, unit=UnitOfMeasure.U_L), plate.wells()[2])

# Fails when trying to run this step.
pipette.aspirate(Amount(amount=10, unit=UnitOfMeasure.U_L), plate.wells()[1])

Current behavior

Fails to address back-most row of wells even though this row is accessible (e.g. when running in standard 8-channel layout)

Expected behavior

can access all wells of labware in row A with tip A1.

Operating system

None

System and robot setup or anything else?

No response