Chart title formula syntax error

The formula syntax for chart titles raises an error when referencing a name that contains 2 dots or more, examples:
=Sheet1!a..
=Sheet1!my.name.ref
Using workbook or full reference instead of sheet doesn't work either.
Using VBA works (.Formula = "=Sheet1!a.."), yet reentering it raises a syntax error.

Another quirk, if you enter only = in chart title formula, it turns into ="""=""" and the title shows only = (instead of "=").
Reentering ="""=""" would correct title to "=".

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