Shokz open run battery

Hey guys - I currently use the Shokz Open Run and haven’t had any issues with battery life till now. I used them for my marathon and they died at mile 20 (ugh😭) and now the battery is down to medium after only an hour of use. They are supposed to have around an 8 hour battery life from what I read? I just purchased them this summer so they are fairly new. Any one else have any issues like that or is this normal?