Proton Pass for Proton Unlimited users is currently advertised as allowing "Securely share vaults with other Proton Pass users" with "10 others". But if the other Proton Pass users are on Proton Free accounts, there is actually another limitation of only two Proton Free users per shared vault.

Even though a Proton Unlimited user can send share invitations to more that two Proton Free users, after the second Free user accepts their invitation, any other Free user receives an error message stating "This vault has reached the limit of users", which is not true.

That is not what is being advertised by Proton at all. According to the Pricing page and to the documentation, there are no such restrictions. Enforcing such restrictions is misleading.

Moreover, such restrictions make no sense at all. Increased sharing limits for vaults is a Proton Unlimited feature, independent of other users' business relationships with Proton.

Please consider lifting this limitation or rephrasing what is being advertised for Proton Unlimited users. For instance, it would be more accurate as "Any paid Proton Pass plan: Create and share up to 50 vaults, with up to 10 users per vault (including yourself and limited to two Proton Free users)".