I had this issue since 3 weeks. After xcode 9.3 update, I couldn't run ad-hoc build on the device with enterprise account. It was asking to trust developer on settings but you don't need to trust developer on ad-hoc build, you just need to add device uuid to provision profile. Also there is not an option about it on device management section on settings, if ipa file was generated via ad-hoc distribution. I tried with newly generated ad-hoc provision profile but there was no luck. I tried newly created project with new app id and still no luck. I think there are some changes about ad-hoc distribution on enterprise account or some bugs. I used company account to export ad-hoc build to workaround the issue.
some changes or
some bugs らしいが、たぶん
some bugs だろう。「信頼する」手段がないのだから。
AdHocを用意したいなら、Enterpriseではない通常の「Apple Developer Program」じゃないと駄目なようだ。えぇ...