Failed statement when it's not suppose to be

Hi!

I'm using Grassblade LRS to use with Learndash within our WordPress website. When I first tried to test a simple course (true/false question +  a result slide - TinCan export, result slide selected), everything worked fine and the statement sended to my LRS was good.

 verb : { 
id : http://adlnet.gov/expapi/verbs/passed 
}, 
result : { 
duration : PT0H0M5.51S, 
completion : true, 
success : true, 
score : { 
scaled : 1 
}

Then, I tried to upload my 700mb course with the same publish setting. In that course, there's three different result slides, but the last result slide is the only one that I want to get the result from (the other two first result slide is only informative for the user).  But when I test my course, my LRS got only a "failed" statement from the result slide, even if the statement of each question linked to that slide got the statement "passed". The JSON file show that information :

{ 
version : 1.0.0, 
result : { 
success : false, 
score : { 
min : 0, 
scaled : 0, 
raw : 0, 
max : 7 
}

Why my course send a min/scaled/raw/max information (with no value in it) instead of a "completion:true" statement like first my test ?

I really need your help with that issue! Thanks!!!