Since the G33 is rated at 5hz, which means 5 updates of GPS position data per second.
Evidently, DeLorme was able to handle the extra data (despite it also ONLY support 1 hz / 1 update per seconds).
Have you attempted to downgrade the GPS to 1hz from 5 hz and re-test?
Please response with your test result.
FYI: Attached is the GPS utility to re-configure the update rate.