You forwarded a lot at once, or a provider sent a stack of documents, and only part of it filed.
In Rhodes: Settings → Mailbox
When unusually heavy mail lands in one day — more than 60 emails with attachments across your workspace, or more than 16 from one sender — Rhodes stops auto-filing the overflow and holds it for you instead. Senders on your Trusted senders list aren't held by the per-sender limit. This is a volume check on the email path, not a judgement about the documents.
Nothing is lost. Every held email is received and recorded, and the held items are listed in Settings → Mailbox. Press File it anyway on the ones you want processed.
Owners and admins get one notice about it per day, however many are held. The count resets daily.
Doing a deliberate bulk load? Upload from the Processing page or in chat instead of emailing it in, up to 100 files at a time. The email volume check doesn't apply there.