Text Attributes (Input type text) are missing on order save

I thought the following problem was caused by dropdown attributes module but it is not : https://www.drupal.org/node/2640070

so I have to post here as well.

I have some attributes (select list + text) attached to products.

When I added product to my cart, these attributes are shown very well. I can confirm ubercart_cart_product table has the following data : (I have unserialized them here )

array (
'attributes' =>
array (
2 => '4',
8 => '24',
37 => 'Person 1',
10 => '33',
40 => 'Person 1',
41 => 'Person 2',
42 => '',
5 => '14',
46 => 'Person 1',
47 => 'Person 2',
48 => 'Person 3',
9 => '',
25 => '',
11 => '',
28 => '',
29 => '',
30 => '',
6 => '',
34 => '',
35 => '',
36 => '',
),
'shippable' => '0',
'type' => 'product',
'module' => 'uc_product',
)

But when I proceed to check out, the text attrbiutes are gone!
This is the unserialized data from uc_order_products :

array (
'attributes' =>
array (
'Select Your Room Type' =>
array (
4 => 'Single Room',
),
'Do you have accompanying children (0-2 Ages) ?' =>
array (
24 => 'Yes',
),
'1. Kid (0-2 Ages) Name&Surname' =>
array (
0 => '',
),
'How many accompanying children (3-6 Ages) ?' =>
array (
33 => '2 Kids',
),
'1. Kid (3-6 Ages) Name&Surname' =>
array (
0 => '',
),
'2. Kid (3-6 Ages) Name&Surname' =>
array (
0 => '',
),
'3. Kid (3-6 Ages) Name&Surname' =>
array (
0 => '',
),
'How many accompanying person ?' =>
array (
14 => '3 Adult Person',
),
'1. Person Name&Surname' =>
array (
0 => '',
),
'2. Person Name&Surname' =>
array (
0 => '',
),
'3. Person Name&Surname' =>
array (
0 => '',
),
),
'shippable' => '0',
'type' => 'product',
'module' => 'uc_product',
)

As you can see all --- array(0 => '',) --- I am missing my text attributes there. (Select type attributes seem to be fine)

Upon further invastigation as weird as it sounds, when attribute labels are unique, they are shown in checkout as well. If attrbiute labels are not unique and if they share the same label, they are not visible in checkout and invoices, order details.

could you please help?