Can't anonymize fields containing <ip-addr>:<port>

[pavdmyt]

I'm having multiple logs entries with ipPort field with values like this: 192.168.0.1:8080. Trying to use anonymizer with the following config does not produce desired result:

<source>
  @type dummy
  tag raw.dummy
  dummy [ {"ipPort":"10.102.3.80:5555","member_id":"12345", "mail":"[email protected]"} ]
</source>

<filter raw.**>
  @type anonymizer

  # Specify rounding address keys with comma and subnet mask
  <mask network>
    key_pattern .*
    ipv4_mask_bits  0
    ipv6_mask_bits  0
  </mask>
</filter>

<match raw.**>
  @type stdout
</match>

Gives:

2020-06-22 17:17:46.099515554 +0000 raw.dummy: {"ipPort":"10.102.3.80:5555","member_id":"12345","mail":"[email protected]"}

Probably plugin does not recognize value 10.102.3.80:5555 as an IP address, hence skips it. Is there any workaround to handle such cases?