Transport Rule - Recipient Limit

The limits for Transport rules documented here: technet.microsoft.com/.../exchange-online-limits.aspx

Only way to get an exception is to open a support case.

Hi Briantgrant,

According to the limits for Transport rules, when a message is acted on by different transport rules in Exchange Online, 100 recipients can be added to the message. After the limit is reached, any remaining recipients aren't added to the message.
If you want to increase this, I suggest you submit feedback via https://office365.uservoice.com/forums/273493-office-365-admin.
Understanding your experience helps us to make our product and service better for you and others.

Back to your issue, since you have created the rules via PowerShell and now some recipients in the rules are missing, I suggest you run the admin audit log report to check if there is any related information.

Thanks,
Franky

As I wrote.. I am already in the process of requesting an increase (Premier Support).

And yes, I found the page  that shows 100 limit.

And yes, I can see in the audit log that I created the Transport  Rules & that nobody no admin appears in the log having deleted them. This customer for example was moved form FOPE to EOP . And is  a Global Organization with presence in over 60 countries. So, this is basically limited them to less than two per country.

We are actually performing a migration from on-premise 2007 Exch. and this issue puts a halt in the project.

And performing a   client-side redirect for 12 of the accounts after still performing the Transport Rule changes is notoriously unreliable and doesn't help at all in the future .

The work around is to set Stop processing more rules  and then the count no longer goes up.

Luckily this is a possibility.. So, each Rule that you have a mail directed towards another mail address use Stop processing more rules   and you can avoid the 100 recipient limit