Calc deleting entire sheets of XLSX files

I have an Excel XLSX file, which if opened in Excel 2007 contains many lines of data in one of its tabs.
But if the same file is opened in CALC (LibreOffice version that tab displays as entirely empty.

(A previous instance of this bug a few days ago showed that if I save the file opened in Calc with data missing, then that data is permanently gone. Another instance of this problem had a large number of rows being cleared/deleted off the bottom of a large sheet (i.e. higher numbered rows went missing). )

Today I showed that if I close CALC without saving, then reopen the file with Excel, the data is still there. I cycled through the process, opening/closing in CALC then opening/closing in Excel a few times to verify the bug.

Then I made an edit to that tab via Excel. Now opening in CALC succeeds and shows the tab with all its data.

I have attached screenshots showing the tab empty on a MAC running LibreOffice and showing the tab full of data on a PC running Excel 2007.

But after the above edit, my file is not CURRENTLY reproducing the issue, so I have not attached the file. Since this has happened repeatedly in the last few days, CALC is no longer trustworthy. And CALC is deleting tabs that I don’t even see, so if I opened spreadsheet to edit tab A but silently tab B was cleared, then I save the file, I might not find out for days or weeks that tab B got cleared.

This is a critical bug. Has this been seen by anyone else? Is there an older version of LibreOffice I should revert to?

Thanks for any help!

PC Excel screen shot of tab with data

Mac LibreOffice Calc screen shot of emptied tab

(edit: activated screenshots)

Perhaps in relation with this

Bug 97597 - FILEOPEN: XLSX file on server opens with some blank tab pages (workaround: export MAX_CONCURRENCY=1)

Yes, that seems to match the “entire tabs empty” issue.
But sometimes only many rows near the bottom are missing.
Would that fit too?

Please test with a master build.