Slave device gets no data

A slave device gets no data, even it's a copy from another slave device and the master is getting data.

Master:
```
Internals:
.FhemMetaInternals 1
ADDRESS feinstaubsensor.fritz.box
DEF local feinstaubsensor.fritz.box
FUUID 5fbd797f-f33f-0f53-b10d-f1c15edb0345c39d
FVERSION 59_LuftdatenInfo.pm:0.219370/2020-05-14
INTERVAL 60
MODE local
NAME out.sensors.environment.6
NR 9267
STATE device_alive
rssi_bad
TIMEOUT 5
TYPE LuftdatenInfo
.attraggr:
.attrminint:
.userReadings:
HASH(0x55f5975eb198)
HASH(0x55f5975eca38)
Helper:
DBLOG:
activity:
general.system.log.db:
TIME 1606311878.96102
VALUE alive
date:
general.system.log.db:
TIME 1606311878.96102
VALUE 24.11.2020
max_micro:
general.system.log.db:
TIME 1606311878.96102
VALUE 379056
min_micro:
general.system.log.db:
TIME 1606311878.96102
VALUE 398
rssi_quality:
general.system.log.db:
TIME 1606311878.96102
VALUE rssi_bad
samples:
general.system.log.db:
TIME 1606311878.96102
VALUE 1747075
signal:
general.system.log.db:
TIME 1606311878.96102
VALUE -86
softwareVersion:
general.system.log.db:
TIME 1606311518.72106
VALUE NRZ-2018-111-AF-070
state:
general.system.log.db:
TIME 1606311878.96102
VALUE active
time:
general.system.log.db:
TIME 1606311878.96102
VALUE 21:52:10
READINGS:
2020-11-25 14:38:38 .sensors BME680_air_quality BME680_humidity BME680_pressure BME680_pressure_nn BME680_quality_data BME680_temperature DHT22_humidity DHT22_temperature SDS011_P1 SDS011_P2 max_micro min_micro samples sensor_start_date sensor_start_time signal
2020-11-25 14:44:38 activity alive
2020-11-25 14:44:38 activity_state device_alive
2020-11-25 14:44:38 date 24.11.2020
2020-11-25 14:44:38 max_micro 379056
2020-11-25 14:44:38 min_micro 398
2020-11-25 14:44:38 rssi_quality rssi_bad
2020-11-25 14:44:38 samples 1747075
2020-11-25 14:44:38 signal -86
2020-11-25 14:38:38 softwareVersion NRZ-2018-111-AF-070
2020-11-25 14:44:38 state active
2020-11-25 14:44:38 time 21:52:10
Attributes:
alias Feinstaubsensor Tulpenweg / Nelkenweg
devStateIcon rssi_good:it_wifi@42BC0A rssi_medium:it_wifi@sandybrown rssi_bad:it_wifi@E50005 rssi_check:unknown@gray
device_alive:device_alive@42BC0A device_dead:device_dead@E50005
group Feinstaubsensor Tulpenweg / Nelkenweg
icon air-pollution@black
interval 60
rawReading 1
room Außen->Sensoren->Umwelt
sortby 100
stateFormat activity_state
rssi_quality
userReadings activity {
return (ReadingsVal($name, q(state), q(error)) eq q(active))
? q(alive)
: q(dead);
},
rssi_quality:signal:.+ {\
return FHEM::MyUtils::Readings::rssi_quality($name, q(signal));
},
```

Slave (with data):
```
Internals:
.FhemMetaInternals 1
DEF slave
out.sensors.environment.6
SDS011_P1 SDS011_P2
FUUID 5fbd8db3-f33f-0f53-ba6e-f68164122851768e
FVERSION 59_LuftdatenInfo.pm:0.219370/2020-05-14
MASTER out.sensors.environment.6
MODE slave
NAME out.sensors.environment.6.sds011
NR 9270
SENSORS SDS011_P1 SDS011_P2
STATE device_alive
TYPE LuftdatenInfo
.attraggr:
.attrminint:
.userReadings:
HASH(0x55f5975edd50)
Helper:
DBLOG:
PM10:
general.system.log.db:
TIME 1606311170.10616
VALUE 13.35
PM2.5:
general.system.log.db:
TIME 1606311170.10616
VALUE 9.88
activity:
general.system.log.db:
TIME 1606311170.10616
VALUE alive
state:
general.system.log.db:
TIME 1606311170.10616
VALUE active
READINGS:
2020-11-25 14:32:49 PM10 13.35
2020-11-25 14:32:49 PM2.5 9.88
2020-11-25 14:32:50 activity alive
2020-11-25 14:32:50 activity_state device_alive
2020-11-25 14:32:49 state active
Attributes:
alias Feinstaubsensor Tulpenweg / Nelkenweg - SDS011
group Feinstaubsensor Tulpenweg / Nelkenweg
icon circuit@black
rawReading 1
room Außen->Sensoren->Umwelt
sortby 130
stateFormat activity_state
userReadings activity {
return (ReadingsVal($name, q(state), q(error)) eq q(active))
? q(alive)
: q(dead);
},
```

Slave (no data):
```
Internals:
CFGFN
DEF slave
out.sensors.environment.6
SDS011_P1
FUUID 5fbe5d8d-f33f-0f53-7c98-011fc0a78ec83a43
MASTER out.sensors.environment.6
MODE slave
NAME out.sensors.environment.6.sds011.pm10
NR 22547
SENSORS SDS011_P1
STATE active
TYPE LuftdatenInfo
.attraggr:
.attrminint:
Helper:
DBLOG:
state:
general.system.log.db:
TIME 1606312059.10391
VALUE active
READINGS:
2020-11-25 14:47:38 state active
Attributes:
rawReading 1
```

`defmod`ing the slave without data didn't help, also didn`t renaming it.