I posted this challenge an hour ago.
At the time of writing this, it has 14 votes. When I check rep gained from it however, it only shows that I've gained 30, even though 14 * 5 = 70:
This is the only rep I've gotten on PPCG in the past day (besides 2 for accepting an answer), so I shouldn't have hit a rep limit.
The main site shows the same thing, so this isn't just a display bug in the Android app.