Calc text function stopped working

A LibreOffice Calc spreadsheet (Linuxmint OS) with a small column of LEFT(A1,2) type text functions in Column B, with the source text in Column A (obvously), and all cells pre-formatted to “text”, will not now accept new text functions of the same type. Nor is it even now possible to delete and retype a couple of characters in an existing formula and not be left with the function showing rather than the result. I am not aware of doing anything that caused this.

Only possible candidate is insertion of “character” or “shape” elsewhere in the spreadsheet, but in any case, problem still exists in trying to create a new spreadsheet with just test text data and text functions.

The standard Cntrl F8 “to show value” and" Cntrl` or Cntrl~ “to show formula/results” all work as expected on formulae entered earlier BUT it seems that new ones, even on a new spreadsheet, or even a modified old ones will not enter and execute. They just sit there as a text formula.

Its like the keyboard is now startedputting in an extra invisible corruption character. As mentioned above, even deleting the letters “LEFT” in the above function and retyping the replacement letters in, leaves a formula showing, and the only way back is to using cntrl-z to revert to old value.

I have shut and rebooted the computer to no avail. I am running Linuxmint Cinnamon about 18.3 and everything else is fine. I can, for example enter new maths type like SUM(A1:A8) in a number formatted range and that works OK. It’s just the text functions that seem to not work.

Now to answer my own question, as I finally worked out the problem, and what was stopping my question from posting!!.

The “text function” mentioned was processing time related data in the form 12:34, for 12 minutes and 34 seconds, as this was the only way I could get things to behave. Part of that was to format the cell into which the above was typed as “text”.

The problem came when I needed to add more data and formatted a whole area of my spreadsheet as “text” in advance - and the problem with that is that text function formulae have to be entered into cells that are in the formatted as “all” or “number” for the function to work, If not the function shows as a “text” report of that it is, and does not execute and give a “text” answer.

In my case I was wanting LEFT(Cell,2) of a cell with 12:34 as text to report 12, so that I could then multiply that by 60 and add the RIGHT(cell,2) quantity of 34 (as above) to get a final answer in seconds.