Might as well try my luck here as someone else may have had a similar experience, or I've overlooked a resource on it.
We have used the default MoH Music from the UC on all our deployments to date. The primary reason for this is something that we are only now troubleshooting as time has finally allowed us to followup some of the 'non-essential' items.
There are two issues we currently facing across a number of our deployments, our own internal included;
1) MoH Onboard (Flash File Default)
When this is enabled on some of our systems it will sometimes work, other times not. Other times if you wait on hold for an extended period of time, it will cut in and out at random intervals, whether it be 30 second blocks, or every few minutes. Sometimes it never plays, other times it plays without issue.
2) MoH Port
We have a similar issue with the MoH port, where by sometimes it will play the MoH port input (We are testing with a PC output into the MoH port) and other times it will revert to the MoH file on the UC. Othertimes I have been testined (internal and external calls) and it will cut in between the UC Default and the MoH port at irregular intervals.
Surely we are not the only ones that have experienced this? Originally I thought it was a hardware fault, however now thats its been identified across several sites, on varying hardware configurations, I'm wondering if its something in our custom configs that are causing these errors or....?