"making it questionable" is correct and usable in written English.
You can use it when you are questioning the accuracy or reliability of something. For example, "He offered no proof to back up his claim, making it questionable".
Cellino already has two criminal convictions, making it questionable whether he will pass the Football League's ownership test.
-Nearly 30 companies are developing thin-film modules based on CIGS or CIS compounds, making it questionable how many will survive the current economic climate.
However, the text is ambiguous, making it questionable that Henry ever matures.
No synchronous stroking of the hands was employed, making it questionable if an ownership-illusion was ever produced.
The validation studies were methodologically weak and heterogeneous, making it questionable to compare the case definitions.
However, c-Jun was also induced and lef1 also downregulated in p53-negative cells, making it questionable whether p53 contributed to their regulation after DNA damage (Supplementary Figure S5C).
He added, "The fact that it is so inflammatory makes it questionable.
But most were of the view that the volume of material included made it questionable whether the new curriculum would ever actually be taught in full to pupils.
However, OFDM has some important drawbacks that make it questionable for future wireless systems as 5G networks [2].
Because the identification of welfare with preference satisfaction makes it questionable whether one can make interpersonal welfare comparisons, few economists defend a utilitarian view of policy as maximizing total or average welfare.
Importantly, research shows that people are fairly limited in their ability to predict their future behavior, which makes it questionable whether self-reported intentions are valid proxies of real-world behavior, especially in situations that are uncommon or situations that regard unconventional behavior (Exum & Bouffard, [2010]).
