Client Type (ex. PC, Android, Webclient): Windows Client Version (if known. Webclient has no version.): v2.7.1 When did you first notice the bug?: Using the teambuilder. Have you been able to reproduce the bug?: Yes. Information (include relevant logs, replays, screenshots): Vulpix in the screenshot should not still have max stats. In Generation 7, Hyper Training normally makes it so that you don't have to drop any of your stats by a point to run Hidden Power. However, in order to accomplish Hyper Training in-game, Pokemon have to be at level 100, which means that this cannot apply to Little Cup because it is at level 5.
In the next update the hp choice box will be readded. You'll have to choose one of those iv sets after you pick the power. Android is kind of screwed though :(. If you want I can have it change ivs once the battle starts to match the hidden power (if it doesn't already).
Changing the IVs to match the appropriate Hidden Power if it doesn't already match would be a possible solution because the main issue is that running max IVs for a Hidden Power type (other than Dark) shouldn't be legal in LC since the hyper training doesn't apply.