Data loss in xlsx sheet - maximum number of columns per table was exceeded

Recently I’ve updated my Unbuntu 18.04 NC from 18.0.8.1 to 18.0.9.1. After that I’ve opened a xlsx document in NC and there is one sheet in that document without content where the previously was content. I don’t know if the NC-update has anything to do with the problem of the missing sheet. A few days before, I did update from Onlyoffice 6.0 to 6.0.2. However , there was no issue with this document. I’ve opened, closed and modified it several times.

I don’t know if this is related to the problem or not, but the change date of the file still shows me that I’ve changed it 6 days ago, even though I’ve modified it yesterday. This is something I’ve also noticed for weeks and month, but it was not a problem because there was not missing information from the doc.

In that sheet there were 2 text boxes with formatted text (bold word), full URL’s and linked words with URL’s. There are also lot’s of special characters like +"%Y%m%d".bak

Then I’ve downloaded full workbook from NC and opened it with Libreoffice. It gave me the following error message. I believe this is related to the missing sheet because when I completely deleted that faulty, empty sheet (not the entire workbook though), I close the workbook and reopen it and then the error message is gone.

here is the error message:

Warning when loading the document filename.xlsx:
The data could not be loaded completely because the maximum number of columns per table was exceeded.

log-entries

It looks like a bug to me. I did re-upload my backup-workbook to NC and so far no issues with the file. However, I think this bug should be fixed because it happened to me before and I’ve lost a lot of data.
Somebody who has experienced the same? Is there any possible solution?

I had a similar case but with gnumeric. Excel would report an error and, after being fixed, all formatting was gone. LibreOffice Calc was a bit better. It reported the correct problem and handled it so that no loss was noticeable.

Possibly a bug, yes, but the question is on which side exactly.

I suspect an operation while the whole row was selected. In Excel and Calc this will, in my experience, only affect the used cells and will not store the formatting for all 16K cells in a row.