Abhishek,
I am glad to hear the garbled item fix is on the horizon. As to the slowness, I was able to resolve it after noticing the sync database and the backups had grown significantly. Here significantly means the sync database growing from about 38MB with over 500 items to almost 500MB and the backup file growing from 18MB for three different vaults to over 350MB.
I was able to shut off sync on the two windows computers, and an Android phone, and then reinstall on one of the Windows machines starting with a backup. Then setting up sync again on the other devices. All seems to be humming along as before now.
If I can provide any more information about the root cause of the problem, I will need some direction. However, I am content for now that everything is working well.