weird issue when recording data

[michael040101]

Hi,
Im using ubuntu 20.04 and gnuradio 3.8.5, and i get the following error,

michael@ubuntu:~/Desktop/gr-iridium-maint-3.8$ iridium-extractor -D 4 examples/rtl-sdr.conf > output.bits
gr-osmosdr 0.2.0.0 (0.2.0) gnuradio 3.8.1.0
built-in source types: file osmosdr fcd rtl rtl_tcp uhd miri hackrf bladerf rfspace airspy airspyhf soapy redpitaya freesrp
[INFO] [UHD] linux; GNU C++ version 9.2.1 20200304; Boost_107100; UHD_3.15.0.0-2build5
Found Rafael Micro R820T tuner
Using device #0 Realtek RTL2838UHIDIR SN: 00000001
Found Rafael Micro R820T tuner
[R82XX] PLL not locked!
Exact sample rate is: 2000000.052982 Hz
[R82XX] PLL not locked!
(RF) Gain: 19.7 (Requested 19)
WARNING: Gain if not supported by source!
Supported gains: ('LNA',)
Warning: Setting antenna to RX
1646954261 | i: 0/s | i_avg: 0/s | q_max: 0 | i_ok: 0% | o: 0/s | ok: 0% | ok: 0/s | ok_avg: 0% | ok: 0 | ok_avg: 0/s | d: 0
Traceback (most recent call last):
File "/usr/local/bin/iridium-extractor", line 373, in
tb.run()
File "/usr/local/lib/python3.8/dist-packages/iridium/iridium_extractor_flowgraph.py", line 435, in run
self.start(*args, **kwargs)
File "/usr/lib/python3/dist-packages/gnuradio/gr/top_block.py", line 111, in start
top_block_start_unlocked(self._impl, max_noutput_items)
File "/usr/lib/python3/dist-packages/gnuradio/gr/runtime_swig.py", line 4832, in top_block_start_unlocked
return _runtime_swig.top_block_start_unlocked(r, max_noutput_items)
RuntimeError: list contains invalid format!

Do you have any idea why does it happen?

thanks!