I imported your ZIP file with both the "new" Cloud Editor and the "old" Cloud Editor and it worked as expected both times.
I wonder if it might be caused by you not having sufficient storage allocation in your Arduino Cloud account to accommodate the full sketch. You can check how much of your storage allocation is used by opening this page:
https://app.arduino.cc/plan-usage
Does that page show that you have enough storage available for a >1.5 MB sketch?