There are cases, where the error message differs, when an expression is being parsed inside an fstring. For example:

>>> f'{x+}'
  File "<fstring>", line 1
    (x+)
       ^
SyntaxError: unexpected EOF while parsing
>>> (x+)
  File "<stdin>", line 1
    (x+)
       ^
SyntaxError: invalid syntax

Or with lambda definitions:

>>> f'{lambda x:x}'
  File "<fstring>", line 1
    (lambda x)
             ^
SyntaxError: unexpected EOF while parsing
>>> (lambda x)
  File "<stdin>", line 1
    (lambda x)
             ^
SyntaxError: invalid syntax