system:time_start error

[VINCENTAFERRER]

Dear Condeça
I have been reading through your good work of estimating reservoir volume using GEE (10.1029/2021WR030026) and trying to use the code for understanding the same in my study area. Thanks a lot for publicly sharing the code and the ancillary datasets. As an initial step I tried executing the code for the Alvito reservoir after importing the shape file of the same as an asset into my GEE portal.
On execution of the code, while the total image collection returned 704 images, the filtered collection showed 0 images and the graph couldnt be plotted as the code was interrupted with the error "No features contain non-null values of "system:time_start"" and the image collection is empty.
Understandably, the issue seem to be related to defining the system time start after reducing the image collection for cloud mask and images without full overlap area. On debugging, I could understand the functions have clearly defined the return function for incorporating the system time start to the output images and still the code could not execute it. And my basic knowledge couldnt troubshoot the exact location where the issue arises.
I would appreciate requesting your support in this regard to relook into the code and provide technical support so that I can use this code to study the reservoir volume changes in my study area.
Awaiting your earnest response, once again thanks a lot for sharing the code....
regards

Vincent A Ferrer
Proj. Scientist - B
Central Geomatics Lab
NCESS, Thiruvananthapuram