Version 0.4.0 (official) - Undo function is no longer working as expected.

documentserver_community: 0.4.0
onlyoffice: 10.1.2

Unfortunately, the Undo function (I did not test Redo) is no longer working as expected.

Although the screen reverts to the previous state after an Undo, that state is not being saved to the file. This results in two completely different states: one on the screen and another in the file.

Sequence of events:

Populate fields: A1, B1, C1, D1
State on screen: A1, B1, C1, D1
Save the state.
State in file: A1, B1, C1, D1

Undo to remove C1, D1 (2 steps)
State on screen: A1, B1
Save the state.
State in file: A1, B1, C1, D1

Additionally populate field: E1
State on screen: A1, B1, E1
Save the state.
State in file: A1, B1, C1, D1, E1

Since saving does not work after an Undo, testing the Redo function is pointless at this stage.

Addendum:

If I overwrite cells C1 and D1 (e.g., with "NEW", "NEW"), these cells are once again included in the saved data.

Apparently, an Undo action is not recognized as a genuine "change event"—unlike, for instance, deleting or overwriting the cell contents.

The error occurs not only when a Redo restores the cells to their original empty state, but also when a Redo restores different cell content (i.e., the cell is occupied both before and after the Redo).

Reproduce the issue with documentserver_community 0.4.0 and onlyoffice 10.1.2 using the A1–E1 sequence described in the report. Compare the on-screen state with the saved file after Undo and Redo, including empty and overwritten cells; done when saved data matches the visible state in these cases.