Failed to add object to RedissonSet

I am using redis 6.0.5 and redisson client 3.14.9

My service on prod fails to add object to RedissonSet.my code looks like this:

redissonClient.getSet(setName).add(newValue)

The add API returns false sometime, meaning failed to add object.I don't see any logs of error, and don't know what could be the reason of failures.