At my company we use a shared mailbox and we used to categorize emails with colors.
Each color to a team member so the member can identify which emails are for him to answer.
Last few weeks we are having some troubles, on my screen (ex.) I see 10 emails to Sophie, 5 to me, and 5 other to Hanna.
On Sophia's screen she see's 2 for her, 10 for me, 3 for Hanna and 5 with no categorie assigned.

That is causing a lot of troubles when trying to count the number of emails each one have per day.

Does anyone know how to solve this?