Only problems with Kymco Like 50

Hello together! Maybe one of you can help me!!! Have a Kymco Like 50 since 09.06. and only problems with it! Let’s say: ONLY A PROBLEM!!!! The scooter suddenly loses power during full-speed driving and gets slower and slower until the engine then runs out at once! And the funny thing is that it always happens at night! Start attempts then fail! The next day the scooter usually starts again without problems! The dealer unfortunately does not find the error. Auc h the importer can’t help me! Does anyone have a tip?? The ADAC said that it could be due to the humidity! The stupid thing is that I’ve been driving a few times in the rain. And he stopped me “only” once. Thanks for your suggestions!