Jallow is 50 on 247's on in-house rankings. It's not clear from the article linked what major services contribute to 247's Composite, but Jallow is ranked 85 on Rivals, 95 on Scout, and a four-star on both. The issue might be with ESPN, which should probably lose its status as a major service at this point.
As noted above, ESPN has two different profiles, one for a Musa Jallow and one for a Musa Jalloh. The former has him graded at 80, which would be in the 100-150 range, while the latter has him graded at 85, which would rank him in the 60's. But ESPN also hasn't updated their 2018 rankings from a top 60 to a top 100 yet, which means they haven't updated their ranking of the 2018 class in a good long while. It also means Jallow currently gets a big fat Not Ranked from ESPN, which is the only reason I can think why his Composite would be in the 140's.
ESPN stopped caring about college basketball recruiting a long time ago, and their reliability has been going downhill for years. If this is what has affected Jallow's profile, it might be worth considering this variable when looking at the profiles of other Indiana targets. Until ESPN starts updating, the in-house rankings on 247 might be more reliable than the composite.