Gated pulse train from a 9401 gets stuck in a high state

I posted recently in the LabVIEW board and I am now running into an issue that I think would be more appropriate to discuss in this board. I am using the attached VI to generate a gated pulse train using an NI 9401 in a NI cDAQ-9171 chassis. I'm running into an error where at certain pulse settings, the gate will trip and be stuck in the high state for the entire duration of the pulse. Attached are photos of the output from the 9401 on a Tektronix 475A oscilloscope.

200us_Gate_a.jpg shows a 4.5 MHz, 50ns signal with a 10MHz, 200us gate. 200us_Gate_b.jpg shows the gate stuck in the high state for the remaining 99.8ms after the 200us gate. While the VI runs, the output on the oscilloscope switches back and forth between 200us_Gate_a.jpg and 200us_Gate_b.jpg with a regular frequency, it's not tripped randomly. I checked the output of the gate pulse on its own and didn't find anything wrong with it, so it looks like something is happening internaly after the signal is routed to the high frequency signal.


My goal is to run this VI with a variety of different gate widths. I've found that if I set the gate to 300us, 600us, or 900us, then the pulse looks fine. Any other value causes the gate to periodically trip and get stuck in the high state. I'd like to bring the gate as low as 100us. Has anyone seen this happen with their counters?