gnuradio 3.9.2 crashes importing gr-bladeRF into flowgraph

[anarkiwi]

I installed GNU radio according to the instructions at https://wiki.gnuradio.org/index.php/InstallingGR#Ubuntu_PPA_Installation (to get the release version, 3.9).

I then built gr-bladeRF (apparently successfully).

However when pasting in the bladeRF Source block, I get the following from gnuradio-companion (which then crashes).

The host platform is Pi4, running Ubuntu focal.

pi@bladerfpi:$ lsb_release -d
Description: Ubuntu 20.04.3 LTS
pi@bladerfpi:$ uname -a
Linux bladerfpi 5.4.0-1042-raspi #46-Ubuntu SMP PREEMPT Fri Jul 30 00:35:40 UTC 2021 aarch64 aarch64 aarch64 GNU/Linux

<<< Welcome to GNU Radio Companion 3.9.2.0 >>>

Block paths:
/usr/share/gnuradio/grc/blocks
/usr/local/share/gnuradio/grc/blocks

Loading: "/home/pi/radiostuff/broadband-scan/broadband_scan.grc"

Done
/usr/lib/python3/dist-packages/apport/report.py:13: DeprecationWarning: the imp module is deprecated in favour of importlib; see the module's documentation for alternative uses
import fnmatch, glob, traceback, errno, sys, atexit, locale, imp, stat
Traceback (most recent call last):
File "/usr/lib/python3/dist-packages/gnuradio/grc/gui/Application.py", line 412, in _handle_action
flow_graph_update()
File "/usr/lib/python3/dist-packages/gnuradio/grc/gui/Application.py", line 121, in flow_graph_update
fg.update()
File "/usr/lib/python3/dist-packages/gnuradio/grc/gui/canvas/flowgraph.py", line 191, in update
self.create_labels()
File "/usr/lib/python3/dist-packages/gnuradio/grc/gui/canvas/flowgraph.py", line 496, in create_labels
element.create_labels(cr)
File "/usr/lib/python3/dist-packages/gnuradio/grc/gui/canvas/block.py", line 182, in create_labels
markups = [param.format_block_surface_markup()
File "/usr/lib/python3/dist-packages/gnuradio/grc/gui/canvas/block.py", line 182, in
markups = [param.format_block_surface_markup()
File "/usr/lib/python3/dist-packages/gnuradio/grc/gui/canvas/param.py", line 178, in format_block_surface_markup
Utils.encode(self.truncate(self.value)) + ""
File "/usr/lib/python3/dist-packages/gnuradio/grc/gui/canvas/param.py", line 96, in truncate
if len(string) > max_len:
TypeError: object of type 'bool' has no len()
Traceback (most recent call last):
File "/usr/lib/python3/dist-packages/gnuradio/grc/gui/DrawingArea.py", line 204, in draw
self._flow_graph.draw(cr)
File "/usr/lib/python3/dist-packages/gnuradio/grc/gui/canvas/flowgraph.py", line 528, in draw
draw_element(cr)
File "/usr/lib/python3/dist-packages/gnuradio/grc/gui/canvas/block.py", line 275, in draw
port.draw(cr)
File "/usr/lib/python3/dist-packages/gnuradio/grc/gui/canvas/port.py", line 131, in draw
cr.rectangle(*self._area)
TypeError: Context.rectangle() takes exactly 4 arguments (0 given)