For the past several months, we've found that the report subscriptions that we've setup (mainly reports in RCE) are very unpredicable. For example, we run 5 standard reports on the first of each month, which are configured to be sent to about 10 marketers. Some will receive 3 of the reports, some will receive 4 and a couple won't receive any at all. As we grow our instance of Marketo, automating the sending of reports will be key to ensure each marketer has the necessary data each month.
We have a ticket opened up with Support and they're suggesting that we try staggering them - send some on one day and the rest the following day. I'm sorry, but that's not a solution. There is clearly a bug in the subscription functionality of Marketo that needs to be fixed.