GM freezes after data synchronization

We’ve recently installed a remote SQL server in the core shack area, which has improved our GM synchronization speed significantly (down to a few seconds). However, after getting a message ‘Synchronization completed’, the software becomes unavailable, perhaps performing some internal operations. This usually takes a few minutes (1 to 5), which slows down the core logging process.

Do you know the reason for this issue, and if we can fix that somehow?