RTL SDR serial not taken into account

[pswiatki]

Got wmbusmeters.conf with the following content:

loglevel=debug
#loglevel=normal
resetafter=10000h
device=rtlwmbus[0000bbb]:CMD(/usr/local/bin/rtl_sdr -f 868.625M -s 1600000 - 2>/dev/null | /usr/bin/rtl_wmbus -s -a)
#device=rtlwmbus[0000bbb]:t1
#logtelegrams=true
#logtimestamps=always
logtimestamps=important
format=json
meterfiles=/var/log/wmbusmeters/meter_readings
meterfilesaction=append
meterfilesnaming=name-id
meterfilestimestamp=day
logfile=/var/log/wmbusmeters/wmbusmeters.log

Everything worked properly (unbeknownst to me it was only by Pure Luck) as long as I had a sole rtl_sdr device in the system.
When I connected a second dongle things immediately went south, because rtl_sdr started picking up the wrong one.
The following situation is reported by the tool:

# rtl_sdr -d some_bogus_serial_no
Found 2 device(s):
  0:  Realtek, RTL2838UHIDIR, SN: 00000aaa
  1:  Realtek, RTL2838UHIDIR, SN: 0000bbb

No matching devices found.

Sure enough, the original was 0000bbb and the new one 00000aaa. Evidently, wmbusmeters started picking up device 0 which was wrong. I suspect SN specification in square brackets as in rtlwmbus[0000bbb] has no effect whrn CMD() clause is in use.
I verified that by adding -d parameter to rtl_sdr (so: /usr/local/bin/rtl_sdr -d 0000bbb -f 868.625M -s 1600000 - 2>/dev/null | /usr/bin/rtl_wmbus -s -a).

Question: do you see anything that is non-standard in these rtl_sdr parameters? I vaguely remember I was instructed to invoke rtl_sdr like this for a particular debug reason, but I - sadlly - forgot why. Perhaps I could just remove the CMD() clause completely and let wmbusmeters handle stuff autoMagically (?)