Unexpected mdsd ack status: ACK_INVALID_SOURCE logs flood

I have two sources i.e. syslog and http. and I want both of these logs to be outputted to mdsd. I tried multiple options to make it work but even if it works in some cases, there is flood of logs in /var/log/td-agent/td-agent.log :
```
unexpected mdsd ack status: ACK_INVALID_SOURCE
```
Options tried :
1. `` without any tag : this works but logs flood with ACK_INVALID_SOURCE
2. `` : does not work
3. Two mdsd plugin i.e. ` and `: works but logs flood with ACK_INVALID_SOURCE

Below is my fluentd conf :
```

type syslog
port 25827
bind 0.0.0.0
protocol_type tcp
tag gheslog

@type http
port 8900
bind 0.0.0.0
body_size_limit 32m
keepalive_timeout 10s ## This source has tag pattern ifx.**

@type mdsd
djsonsocket /var/run/mdsd/default_djson.socket
acktimeoutms 5000 # milli-seconds
num_threads 4
buffer_chunk_limit 2M
buffer_type file
buffer_path /var/log/td-agent/state/mdsd_ifx.buffer
buffer_queue_limit 128
flush_interval 1s
retry_limit 10
retry_wait 10s

```
PS : If I just use single `` with any of these two tags i.e. sending only one source data to mdsd, it works perfectly without any error message.