We are experiencing some stability issues at high load in Zoho Sheet, particularly when Excel documents are imported. Most of the time you would not experience any problem, but when an occasional load spike happens, you may experience glitches, which include garbled data. We are working hard to fix these problems, and enhance system capacity by adding more servers.
We do not intend to keep the beta tag indefinitely, but at the moment, the service is very much beta. So please forgive us for the glitches.
Other Zoho services are not impacted.
Update (2:15 pm, July 5): We just made an update that should fix the immediate issues. We would also be adding more servers to the cluster to handle increasing load.