UART interrupt lost

[DMose]

Under FREERTOS on UART3, I receive a 40 byte packet every 2.5ms @ 921600 baud . I programmed the Rx FIFO to interrupt at 1/2 level threshold. Everything works fine for about an hour. Then, for some reason, I get an overrun condition which seems to mean that the threshold condition did not generate an interrupt as expected. 

Has anyone experienced something like this? 

Thanks

[Tesla DeLorean]

>>which seems to mean that the threshold condition did not generate an interrupt as expected. 

Or you have a task that's not yielding, or a single task doing too much.

Hard to gauge your implementation from the description, but is the task is doing more than just collecting data from the USART, you should perhaps split the other activity into a worker task.