`lastMessage` returns `null` erroneously

[Problem/Question]
I am trying to use this endpoint:
GET https://api-{application_id}.sendbird.com/v3/group_channels
(List group channels | Chat Platform API | Sendbird Docs)

One thing I have noticed is that for a group channel which DOES have existing messages but where the last message in the channel is an ADMIN message, the lastMessage field returns null. This is unexpected behavior. I would expect this field to return either:

  1. the last user or file message sent in the channel
  2. the admin message that is actually the last message sent in the channel

[Frequency]
100% of the time

[Current impact]
Cannot show the latest message in a channel list UI if the last message sent was an admin message