Will OS Patching affect the SQLLOG file Growth in SQL Server Last Sunday we have the OS Patch for the month of June.

Can someone help me understand if the monthly OS patching increases the SQLLOG file in SQL Server ?

Is there any linkage between the OS Patch and SQL Log file first of all ?

What could be the main reason for SQL Log file rapid growth in SQL Server all of a sudden in AlwaysOn AGs environment? 

Is it Maint plans, Backups .....
I don't think there is any direct link between OS patching and SQL Server. The last part of your question when you mention AlwaysOn AGs which could explain the growth.

If you take a replica offline then I believe the log file cannot be truncated even after a log backup because the log file is used to ship the data to the replicas. It will stay in the log file until the replica has confirmed it has the data. So if you have a high-transactional workload and you take the replica offline, the amount of log stored on the primary will grow.

File size increases are also replicated between nodes, so if your logfile grows bigger on the primary then it will also grow on the secondary (once it comes back online).

There's not enough details in the question, but my guess would be that you took the replica offline to patch and during that time the log file on the primary grew as it was waiting for the replication to happen. The growth was then replicated to the replica after it reconnected.