I found some weirdness with copy+paste. I am on Windows 10; have tested with both Brave and Firefox.
I can copy and paste both within the same table in Fibery and between different tables in Fibery with no problems. I can also copy single columns from Excel and paste in Fibery with no problems. BUT:
I CANNOT copy multiple columns and rows from Excel and paste in Fibery, UNLESS the paste action can add a new empty row to the table. E.g., if I copy a matrix of several columns and N rows from Excel I cannot paste it into a table in Fibery unless I select a cell that is on the Nth row from the bottom in Fibery. This also adds a new row to the table.
When i try to paste an N-row matrix that is not on the Nth row from the bottom in Fibery, the correct cell values flash briefly on the screen, but they are not actually added to the table.