In section 3.1.2 of the python documentation, its mentioned as below:

Two or more string literals (i.e. the ones enclosed between quotes) next to each other are automatically concatenated.
This feature is particularly useful when you want to break long strings:
This only works with two literals though, not with variables or expressions:

However, the concatination operation works on variables and expressions also.
Please find the below python code snippet and the output:

Python Code:
-------------
s1='Hello'
s2=' World '
s3=' How are you ? '
print(s1, s2, "\n", s3, "\n")
print('---------------------------')
print('Long time ' 'No see mate ')
print("Hope ", 'All is ' "good")
print('---------------------------')
print(s1, 'World'," !!")
print((s1+s2+s3)*2," there ?")


Output:
--------
Hello  World                                                                                                          
  How are you ?                                                                                                       
                                                                                                                      
---------------------------                                                                                           
Long time No see mate                                                                                                 
Hope  All is good                                                                                                     
---------------------------                                                                                           
Hello World  !!                                                                                                       
Hello World  How are you ? Hello World  How are you ?   there ?

The documentation is correct here; none of the examples you show demonstrates implicit concatenation of string-valued expressions.
The tutorial documentation is referring to two strings placed
directly next to each other with no other syntax (other than
whitespace) in between.

For example, taking just the first line you give (after the definitions):

    print(s1, s2, "\n", s3, "\n")

Nowhere in this line are two string-value expressions placed right next
to each other; they're occurring in an argument list to a function,
separated by commas. The other lines are similar.

I think this issue can be closed (not a bug).