No worries! From our side, the issues you described could only appear from the previous bulk import workflow so we were just trying to understand how you got there. ARW was updated the first week of August. I think the likely explanation was that your browser loaded a cached version of the bulk import submission page instead of the latest version.
Feel free to delete the previous import and try again.
Regarding the maximum number of uploaded encounters, that has always been the recommended guidance because bigger imports will increase wait times for detection and identification for all users of a Wildbook, not just the person uploading the import.
In the past, users have slowed down Wildbooks with imports containing thousands of encounters. This new version of bulk import is helping us enforce those limits to keep the site usable for everyone.