Reply not visible in Mobile Apps

Reply not visible in Mobile Apps
( If there is precedent for this issue, please show me that information. )

I’m experimenting with mattermost.
I installed Mattermost 7.7.1 around February this year, tried it a little, and left it alone,
but I updated it this time.

server: Mattermost Enterprise Edition 8.0.1
schemas: 109
db: mysql 8.0.32
os: CentOS Linux release 7.7.1908

It seems to work mostly correctly, but there are frequent problems.

While connected to the above server with Mobile Apps 2.6.0 (Build 6000479, both of iOS and Android),
It often happens that an existing reply does not appear on the Mobile Apps screen.
For example, a message may say “1 reply” at the end of the message, and a profile pictures of the thread participant are also listed.
When I tap on the message to open it, it says “No reply yet”.
This happens frequently.

Sometimes I can reload by tapping open a message and swiping up, It may load replies that weren’t displayed.
If I could always reload, I would try it, but most of the time the up swipe doesn’t trigger the reload action.

I’ve never had this issue with desktop apps or browser access.
How can I find the problem?
Any advice on this matter would be greatly appreciated.