visual block mode select error

Describe the bug
After I enter visual block mode with Ctrl-V, I try to use Shift+I to insert something, but it seems to get the wrong row.

To Reproduce
I have such context:

#define atomic64_inc_and_test(v)	[my cursor](atomic64_inc_return(v) == 0)
#define atomic64_dec_and_test(v)	(atomic64_dec_return(v) == 0)
#define atomic64_sub_and_test(i, v)	(atomic64_sub_return((i), (v)) == 0)
#define atomic64_add_negative(i, v)	(atomic64_add_return((i), (v)) < 0)
#define atomic64_add_unless(v, a, u)	(___atomic_add_unless(v, a, u, 64) != u)

Ctrl+V and Shift+I and j to go down
I would like to insert before

[my cursor](atomic64_inc_return(v) == 0)
(atomic64_dec_return(v) == 0)
(atomic64_sub_return((i), (v)) == 0)
(atomic64_add_return((i), (v)) < 0)
(___atomic_add_unless(v, a, u, 64) != u)

but I got

[my cursor](atomic64_inc_return(v) == 0)
(atomic64_dec_return(v) == 0)
)	(atomic64_sub_return((i), (v)) == 0)
)	(atomic64_add_return((i), (v)) < 0)
 u)	(___atomic_add_unless(v, a, u, 64) != u)

Expected behavior
I don't know whether it is a bug or my operation is wrong. Thanks a lot.

Reproduce the issue in VS Code using the shown five-line context and the Ctrl-V, Shift-I, then j sequence. Compare the visual block selection and insertion behavior with the expected output; the work is done when insertion occurs before every selected row without moving or truncating text.