@Hari - other than manually editing sheets, some of the reasons for it to show that these may’ve been modified recently are -
- automation functions running inside them (viz. REFRESH, REPEAT, SCHEDULE)
- if these are published apps that folks are able to access by external means
Could you please let me know if either of these scenarios are applicable with respect to these spreadsheets?
Since it’s the weekend, I’d only be able to check with our internal teams to verify them as per our logs by the following week.
Here are a few responses to your other questions as well -
- No
Rows platform does not update sheets on its own
- should there have been a bug, I suspect it would’ve impacted other accounts too but I just checked my official and personal accounts and they don’t seem to show that they’d been updated recently
- had we been migrating functions - which I remember us doing once with merging our older INSERT_DATA, OVERWRITE_DATA & UPDATE_DATA with INSERT, OVERWRITE, UPDATE respectively - we would’ve notified users of the same as that could’ve shown last modified to be at a recent timestamp where users may’ve not made any edits from their end
- At the moment, I have no reason to believe that user accounts at Rows is compromised but I’d definitely recommend changing your password
Your data and spreadsheets are already super secure 
we take privacy and security of these aspects very seriously.
While there’s always our privacy policy that extensively covers all the measures we’ve taken to make that happen, you can also refer our knowledge base articles that should help alleviate some of the concerns you may have on the topic.
