I originally had the game installed on my playdate, I just uninstalled it to reorganize my sideloads, and it too (The original file from 6 days ago), will not install/upload either. It mentions a forward slash issue. I am having this same issue with two other files.
Sorry to hear you've been having issues. I'm assuming this error is occurring with version 1.2? I've made previous versions available to download, so perhaps try those. If the error occurs with older versions, it might be an issue on Panic's side. Also, could I ask what other games you have been having this issue with?
Unfortunate, all three versions are not working, but I can confirm that 24/36 hours ago the file was working fine. So nothing has changed. Please reach out to Panic regarding this if you can. The other games i have had this issue with are "Finstere", "Don't Cross the Streams", "You're_Gonna_Di3", "Starvation" and "Super Date Box". All are free games here.