Autocomplete doesn't insert remaining keyword if cursor is after underscore

[gallor]

This issue is related to #27.

When I enter a keyword and prompt the autocomplete menu I get all the suggestions (I do have set iskeyword+=_ enabled):

I hit tab and select the first item and it fills it in properly:

If I trigger the autocomplete instead after typing the underscore I still get all the correct suggestions:

But if select the next suggestion it ignores the part already there and inserts the whole suggestion:

Is this a setting I'm missing either in my vimrc/coc.config?
Thanks!