Why do Perl 6 state variable behave differently for different files?

Question

I have 2 test files. In one file, I want to extract the middle section using a state variable as a switch, and in the other file, I want to use a state variable to hold the sum of numbers seen.

File one:

section 0; state 0; not needed
= start section 1 =
state 1; needed
= end section 1 =
section 2; state 2; not needed

File two:

1
2
3
4
5

Code to process file one:

cat file1 | perl6 -ne 'state $x = 0; say " x is ", $x; if $_ ~~ m/ start / { $x = 1; }; .say if $x == 1; if $_ ~~ m/ end / { $x = 2; }'

and the result is with errors:

 x is (Any)
Use of uninitialized value of type Any in numeric context
  in block  at -e line 1
 x is (Any)
= start section 1 =
 x is 1
state 1; needed
 x is 1
= end section 1 =
 x is 2
 x is 2

And the code to process file two is

cat file2 | perl6 -ne 'state $x=0; if $_ ~~ m/ \d+ / { $x += $/.Str; } ; say $x; '

and the results are as expected:

1
3
6
10
15

What make the state variable fail to initialize in the first code, but okay in the second code?

I found that in the first code, if I make the state variable do something, such as addition, then it works. Why so?

cat file1 | perl6 -ne 'state $x += 0; say " x is ", $x; if $_ ~~ m/ start / { $x = 1; }; .say if $x == 1; if $_ ~~ m/ end / { $x = 2; }'

# here, $x += 0 instead of $x = 0; and the results have no errors:

 x is 0
 x is 0
= start section 1 =
 x is 1
state 1; needed
 x is 1
= end section 1 =
 x is 2
 x is 2

Thanks for any help.

Answer 1

This was answered in smls's comment:

Looks like a Rakudo bug. Simpler test-case:
echo Hello | perl6 -ne 'state $x = 42; dd $x'.
It seems that top-level state variables are not initialized when the -n or -p switch is used. As a work-around, you can manually initialize the variable in a separate statement, using the //= (assign if undefined) operator:
state $x; $x //= 42;