Graylog Error on inport content pack with Syslog UDP Input

I create a content pack using docker with image: graylog/graylog:4.0 and now I'm importing into image: graylog/graylog:4.0 and image: graylog/graylog:4.0.5 but always have the same error:
**graylog_1 | 2021-02-24 22:50:52,749 ERROR: org.graylog2.shared.inputs.InputLauncher - The [org.graylog2.inputs.syslog.udp.SyslogUDPInput] input with ID <6036d84ad48fe83f83cb8638> misfired. Reason: null**

## Expected Behavior
Import without errors

## Current Behavior
Part of content pack with syslog udp input:
`{
"v": "1",
"type": {
"name": "input",
"version": "1"
},
"id": "6619df96-f068-4257-b002-1952c08f2d78",
"data": {
"title": {
"@type": "string",
"@value": "Nginx"
},
"configuration": {
"port": {
"@type": "integer",
"@value": 12206
},
"recv_buffer_size": {
"@type": "integer",
"@value": 262144
},
"force_rdns": {
"@type": "boolean",
"@value": false
},
"allow_override_date": {
"@type": "boolean",
"@value": true
},
"override_source": {
"@type": "string",
"@value": "Nginx"
},
"bind_address": {
"@type": "string",
"@value": "0.0.0.0"
},
"expand_structured_data": {
"@type": "boolean",
"@value": false
},
"store_full_message": {
"@type": "boolean",
"@value": false
},
"number_worker_threads": {
"@type": "integer",
"@value": 4
}
},
"static_fields": {
"from_nginx": {
"@type": "string",
"@value": "true"
}
},
"type": {
"@type": "string",
"@value": "org.graylog2.inputs.syslog.udp.SyslogUDPInput"
},
"global": {
"@type": "boolean",
"@value": false
},
"extractors": [
{
"target_field": {
"@type": "string",
"@value": ""
},
"condition_value": {
"@type": "string",
"@value": ""
},
"order": {
"@type": "integer",
"@value": 0
},
"converters": [],
"configuration": {
"grok_pattern": {
"@type": "string",
"@value": "%{DATA} %{DATA} %{GREEDYDATA:json}"
},
"named_captures_only": {
"@type": "boolean",
"@value": true
}
},
"source_field": {
"@type": "string",
"@value": "message"
},
"title": {
"@type": "string",
"@value": "JSON Extract from message"
},
"type": {
"@type": "string",
"@value": "GROK"
},
"cursor_strategy": {
"@type": "string",
"@value": "COPY"
},
"condition_type": {
"@type": "string",
"@value": "NONE"
}
},
{
"target_field": {
"@type": "string",
"@value": ""
},
"condition_value": {
"@type": "string",
"@value": "^\\{"
},
"order": {
"@type": "integer",
"@value": 0
},
"converters": [],
"configuration": {
"flatten": {
"@type": "boolean",
"@value": true
},
"list_separator": {
"@type": "string",
"@value": ", "
},
"kv_separator": {
"@type": "string",
"@value": "="
},
"key_prefix": {
"@type": "string",
"@value": ""
},
"key_separator": {
"@type": "string",
"@value": "_"
},
"replace_key_whitespace": {
"@type": "boolean",
"@value": false
},
"key_whitespace_replacement": {
"@type": "string",
"@value": "_"
}
},
"source_field": {
"@type": "string",
"@value": "json"
},
"title": {
"@type": "string",
"@value": "Extract JSON fields"
},
"type": {
"@type": "string",
"@value": "JSON"
},
"cursor_strategy": {
"@type": "string",
"@value": "CUT"
},
"condition_type": {
"@type": "string",
"@value": "REGEX"
}
}
]
},
"constraints": [
{
"type": "server-version",
"version": ">=4.0.2+1987d10"
}
]
},`

LOGS:
```
graylog_1 | 2021-02-24 22:50:52,472 INFO : org.graylog2.inputs.InputStateListener - Input [GELF UDP/6036d84ad48fe83f83cb8615] is now RUNNING
graylog_1 | 2021-02-24 22:50:52,702 WARN : org.graylog2.inputs.transports.UdpTransport - receiveBufferSize (SO_RCVBUF) for input GELFUDPInput{title=Storage, type=org.graylog2.inputs.gelf.udp.GELFUDPInput, nodeId=0a98c7b5-c103-41d3-a70b-0f2aeae919c7} (channel [id: 0xc6cf540b, L:/0.0.0.0:12205]) should be 262144 but is 425984.
graylog_1 | 2021-02-24 22:50:52,717 WARN : org.graylog2.inputs.transports.UdpTransport - receiveBufferSize (SO_RCVBUF) for input SyslogUDPInput{title=Nginx, type=org.graylog2.inputs.syslog.udp.SyslogUDPInput, nodeId=0a98c7b5-c103-41d3-a70b-0f2aeae919c7} (channel [id: 0xf5ade70b, L:/0.0.0.0:12206]) should be 262144 but is 425984.
graylog_1 | 2021-02-24 22:50:52,764 INFO : org.graylog2.inputs.InputStateListener - Input [GELF UDP/6036d84ad48fe83f83cb861d] is now RUNNING

graylog_1 | 2021-02-24 22:50:52,749 ERROR: org.graylog2.shared.inputs.InputLauncher - The [org.graylog2.inputs.syslog.udp.SyslogUDPInput] input with ID <6036d84ad48fe83f83cb8638> misfired. Reason: null
graylog_1 | org.graylog2.plugin.inputs.MisfireException: org.graylog2.plugin.inputs.MisfireException: java.lang.NullPointerException
graylog_1 | at org.graylog2.plugin.inputs.MessageInput.launch(MessageInput.java:158) ~[graylog.jar:?]
graylog_1 | at org.graylog2.shared.inputs.InputLauncher$1.run(InputLauncher.java:84) [graylog.jar:?]
graylog_1 | at com.codahale.metrics.InstrumentedExecutorService$InstrumentedRunnable.run(InstrumentedExecutorService.java:180) [graylog.jar:?]
graylog_1 | at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) [?:1.8.0_282]
graylog_1 | at java.util.concurrent.FutureTask.run(FutureTask.java:266) [?:1.8.0_282]
graylog_1 | at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [?:1.8.0_282]
graylog_1 | at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [?:1.8.0_282]
graylog_1 | at java.lang.Thread.run(Thread.java:748) [?:1.8.0_282]
graylog_1 | Caused by: org.graylog2.plugin.inputs.MisfireException: java.lang.NullPointerException
graylog_1 | at org.graylog2.inputs.transports.UdpTransport.launch(UdpTransport.java:135) ~[graylog.jar:?]
graylog_1 | at org.graylog2.plugin.inputs.MessageInput.launch(MessageInput.java:155) ~[graylog.jar:?]
graylog_1 | ... 7 more
graylog_1 | Caused by: java.lang.NullPointerException
graylog_1 | at org.graylog2.inputs.transports.UdpTransport.launch(UdpTransport.java:130) ~[graylog.jar:?]
graylog_1 | at org.graylog2.plugin.inputs.MessageInput.launch(MessageInput.java:155) ~[graylog.jar:?]
graylog_1 | ... 7 more
graylog_1 | 2021-02-24 22:50:52,998 INFO : org.graylog2.inputs.InputStateListener - Input [Syslog UDP/6036d84ad48fe83f83cb8638] is now FAILED

graylog_1 | 2021-02-24 22:50:53,000 INFO : org.graylog2.inputs.InputStateListener - Input [GELF UDP/6036d84ad48fe83f83cb8643] is now STARTING
```

**One note: Exist one WARN message in all inputs: `WARN : org.graylog2.inputs.transports.UdpTransport - receiveBufferSize (SO_RCVBUF) for input SyslogUDPInput{title=Nginx, type=org.graylog2.inputs.syslog.udp.SyslogUDPInput, nodeId=0a98c7b5-c103-41d3-a70b-0f2aeae919c7} (channel [id: 0xf5ade70b, L:/0.0.0.0:12206]) should be 262144 but is 425984.`
But as you can see in json of contentpack the recv_buffer_size is set to 262144**
`"recv_buffer_size": {
"@type": "integer",
"@value": 262144
},`

## Steps to Reproduce (for bugs)

1. With docker image image: graylog/graylog:4.0 create a content pack with one Syslog UDP input
2. Import in other installation with same image
3. In my case if I go to System/Inputs -> Inputs and see the syslog UDP input state is NOT RUNNING
4. Go to docker logs and see if the error is present in logs..