Hello and welcome,
I don’t think Upload Later was designed to hold onto nominations for days at a time, but for only a few hours, as this should give enough time to allow one to get to an area with a better connection hopefully. This would make sense, since ML takes about 24 hours to decide on a nomination, and if it allows it to go onto community voting after 24 hours, then when a nomination is uploaded using Upload Later after 24 hours, it could go directly into voting.
We also have the option to put nominations on hold after uploading, but if ML gets a look at them while sitting in your Upload Later queue, this might not allow one to use this option.
Personally, I do try to upload all of my nominations at the time I create them. I do sometimes have to edit my nominations after submitting, or put on hold, but it’s usually within a few hours after submitting. I also try to do my research beforehand, so if I do find a potential POI, I might research it at home before creating a nomination at said POI. I use the Notes app on my phone for this, and it might be something to consider using to write down titles/description/supporting info before going out to nominate.
Being that this thread is over a year old, I would recommend posting about this in a feedback thread, such as the one below: