Broken copy paste upon enabling shared workbook [Office 2019]

[mamradzelvy]

Hello,
I have a strange issue which i didn't manage to google sucessfully.

We have a workbook that we newly share between two people, using the legacy version.
We have merged cells in which we enter data, but when we try to copy the data into diferent merged cells, they un-merge again and the data gets pasted into just one of them, in a tiny format.
When we copy the inside of our workbook into a nonshared one, it works flawlessly again, but once we enable workbook sharing in the new document, it breaks the same way.
Any tips?

Here is what im trying to copy.

Here is what happens when i paste it in shared workbook.

Here is what gets pasted in non shared workbook.

 

[Yongle]

Try this workaround until you get a complete solution

Click on cell that is being copied
{F2} to edit (or double click on cell)
{CTRL} a to select contents
{CTRL} c to copy (or rightclick\copy)

Click on target cell
{F2} to edit
{CTRL} v to paste (or rightclick\paste)
{Enter} to confirm