Thread:TMNTSubspace/@comment-3248355-20181030044706/@comment-3248355-20181030050418

Nodoka revealed to own a Gothita but is shown to disobey her commands and which Gothita was too stubborn and bratty to listen. It wasn't until Tough Guy Trials!, Nodoka battled Nanu after Ash lost, Gothita refused to listen to her commands, and that cost her the match, Krookodile's Crunch easily defeated the Fixation Pokémon with only one attack, making Nodoka lose the match and leaving her devastated and very distraught, which made her cry, and the group had to comfort her.

After its defeat, Gothita felt sad about its loss against Nanu, just like Ash did. In Some Kind of Laziness! after Nodoka was protected by Gothita with Psychic from a falling tree, it apologised for being bratty and disobedient, Nodoka forgave it, and Gothita revamped its personality by evolving into Gothorita, and learning Return in the process. With their rekindled bond, Gothorita now listens to Nodoka's commands.

that's how she lost, because of her gothita disobeying her.