Shards initializing randomly

Hello,
I have upgraded my cluster to 7.5.2 around 2 weeks ago, and I'm seeing strange behavior related to shards ever since.
(cluster running on EC2 Centos 7, RPM based Elasticsearch 7.5.2).
For some reason, without any node is shut down or something, cluster health becomes yellow from time to time and I see that a few shards are initializing.

What can be the cause for this behavior that shards initializing without nodes being restarted?

Thanks,
Lior

did u figure this out by any chance?

Hey @Faiz_Ahmed_Mushtak_H,
Acutally I didn't, the issue hasn't occured since I opened this issue.
It did happened for a couple of days but stopped ever since.