Solved
Mascherano not working unless 100%
I gave 8 mascheranos two to upgrade gabriel but it didnt work then same for kvara and tried two times to upgrade de gea with one mascherano to purple but never worked
I'm not sure what your question is here ... you have correctly stated that if the odds are 100% then it will work 100% of the time (ie. every time), whereas if they are not then there is a chance that it won't work.
That's exactly how it is meant to work ... so, yeah, bug report solved i guess 🤷♀️
