[Use integer as field id] error 500 when filtering module by field

hello,
I have a field select in a type 
I have created a flexi module that is showed in the template and display items from this type.
I have set Custom (non-CORE) fields scope  as dynamic, anc insert field_id28 wich is the id of this field, because I want to filter items that have the same value.
at least, if I enable that, I have a 500 error

did I do something wrong ?

Hello

is this a new website that is under development ?

if yes please test by using "Install via URL" in Joomla extension manager:
github.com/FLEXIcontent/flexicontent-cck/archive/3.3.x.zip

I tried it, and it did not work
as soon as I enter a field with this syntax : field_id28 ( for example ) it goes in 500 error

Hello

you need to use proper syntax
see the popup description of the parameter

So I Finally found it with the help of micker.

I just had to enter the id of the field
In my case, just : 28

What makes me wrong : 

In the popup it is written : 

"These filters apply a DYNAMIC filtering, that compares to currently viewed item, so that the item list contains items that have same field values as the current item.
Enter like:
field_id1,field_id2,field_id3"

on the other following field, it is more clear ( I have not seen it )

"These filters apply a STATIC filtering, regardless of current item being displayed.

Enter like:
field_id##value %%
field_id##value

Example:
22##14 %%
47##some field value %%
19##someword

- Single values: field_id##value1

- Ranges: field_id##value1---value2

- Multiple values: field_id##value1+++value2+++value3

- Relation / Reverse-relation: REL_field_id##REL_ITEM_field_id~~value1 " data-original-title="Static filters"

Hello

because field_id28 is converted to integer aka to zero,
the SQL query breaks and you get this error 500