It's unclear why a max upload size limit is set

[Denis-de-Bernardy]

When you reach your allowance for file uploads in a multisite environment, it's not clear why WP will advertise a tiny upload size limit.

For instance, if you can upload up to 10MB of files, with a 2M file size limit, and you've already uploaded 9MB, WP will erroneously report that you can upload up to a 1MB file.

This can lead a multisite newbie to look into php ini files and the like, in order to identify which obscure setting is messing things up, instead of heading straight to the multisite options.

Instead, WP should report that the maximum file size is 2MB, and highlight in a follow-up line that only 1MB is available until the quota is reached.

WP will erroneously report that you can upload up to a 1MB file.

That doesn't sound erroneous to me. That is indeed their limit.

We probably need to be more specific that we're also taking the quota into account, though.