Text boxes disappearing in the chart when closing and opening the file

I have a long set of charts that I prepare for publications (I work as a desktop publisher). The problem that I have is that after preparing a chart, saving and closing it, I frequently need to reopen it. Every time I do that the text box in the title disappears and I have to create a new one (for some special in-house reason the title needs to be a text box, not a chart element). Please see the attached image.

I waste a lot of my time fixing this, because we're talking about 30 or more charts. There is no rule where it happens, with some charts it does, with some charts it doesn't. One solution would be creating a macro that would put back the text box, but of course I would prefer not losing the text box at all.

Regards,
Robert

I use Excel 2016.
Please find attached a simple workbook. Chart2 is the correct sheet.
Thank you.