core: Modbus error with 2021.5.0

The problem

Shortly after upgrading to 2021.5 my system becomes unresponsive and Lovelace won’t load. In the logs I see an error about modbus (see below). I use modbus for connecting to my solar inverter (see below yaml). restored and upgraded again to confirm this is caused by 2021.5.0

What is version of Home Assistant Core has the issue?

2021.5.0

What was the last working version of Home Assistant Core?

2021.4.6

What type of installation are you running?

Home Assistant OS

Integration causing the issue

modbus

Link to integration documentation on our website

https://www.home-assistant.io/integrations/modbus/

Example YAML snippet

modbus:
  type: tcp
  host: 192.168.8.1
  port: 502
  sensors:
    - name: PV inverter model
      address: 30000
      count: 15
      data_type: string
    - name: PV inverter power max
      address: 30075
      count: 2
      data_type: uint
      device_class: power
      unit_of_measurement: W
    - name: PV voltage
      address: 32016
      data_type: int
      scale: 0.1
      precision: 1
      device_class: voltage
      unit_of_measurement: V
    - name: PV current
      address: 32017
      data_type: int
      scale: 0.01
      precision: 2
      device_class: current
      unit_of_measurement: A
    - name: PV input power
      address: 32064
      count: 2
      data_type: int
      device_class: power
      unit_of_measurement: W
    - name: PV daily active power peak
      address: 32078
      count: 2
      data_type: int
      device_class: power
      unit_of_measurement: W
    - name: PV active power
      address: 32080
      count: 2
      data_type: int
      device_class: power
      unit_of_measurement: W
    - name: PV total production
      address: 32106
      count: 2
      data_type: uint
      scale: 0.01
      precision: 2
      device_class: energy
      unit_of_measurement: kWh
    - name: PV daily production
      address: 32114
      count: 2
      data_type: uint
      scale: 0.01
      precision: 2
      device_class: energy
      unit_of_measurement: kWh

Anything in the logs that might be useful for us?

2021-05-05 20:49:05 ERROR (MainThread) [homeassistant] Error doing job: Future exception was never retrieved
Traceback (most recent call last):
  File "/usr/local/lib/python3.8/concurrent/futures/thread.py", line 57, in run
    result = self.fn(*self.args, **self.kwargs)
  File "/usr/src/homeassistant/homeassistant/components/modbus/sensor.py", line 232, in <lambda>
    self.hass, lambda arg: self._update(), self._scan_interval
  File "/usr/src/homeassistant/homeassistant/components/modbus/sensor.py", line 300, in _update
    registers = self._swap_registers(result.registers)
AttributeError: 'ModbusIOException' object has no attribute 'registers'

Additional information

No response