I've noticed, on rare occasion that if the ATC is talking to me, or I am responding to the ATC, and I happen to be crossing a waypoint at the time. After I finish I will be contacted by the ATC telling me I am off the airway, even though I am not.

RC4 will not credit a waypoint if you are talking to ATC and have not acknowledged it. If you carry out instructions promptly and ack it should not be a problem. Lack of an ack can stall RC's recognition of your waypoint crossing.

 

Investigate the option of direct next checkpoint available through the extended menu (9) by default to have RC skip that missed waypoint and advance to the waypoint you select. This means, like on resume own navigation, you go direct from your present position to the waypoint you selected. If using auto pilot coupled navigation, know how to "pop" the navigation stack or use its direct-to option.

Thank you, I found it, I'll use this the next time I have this issue.