Air carrier First Officer reported during initial climb the radio altimeter was giving erroneous information. The crew suspected 5G interference. During cruise flight an access door became loose and the crew contacted maintenance. The flight continued to its destination.

Narrative

Captain was flying the leg. Immediately after rotation from Runway 34 in HPN the first officers RA flagged and showed negative 5 ft. That continued until approximately 1;400-1;500 ft. Then normal RA indications resumed. This only occurred on the first officers Primary Flight Display. We notified Tower of the RA issue and continued the flight. After reaching cruise we experienced a hydraulic door open ICAS message. After completing the Quick Reference Handbook I contacted [Commercial Radio] for a phone patch to my Dispatcher and Maintenance Control. After speaking with Maintenance we agreed that it was a possible door switch malfunction and the flight was safe to continue to ZZZ. The entire process with the phone patch took approximately 45-50 minutes. After this I set the plane up for a normal arrival into ZZZ. We landed with all indications normal. I wrote up the hydraulic door indication but forgot to write up the possible 5G interference. I was busy contacting Local Maintenance to tell them about the hydraulic door issue which was on the fore front of my mind. I usually write up items at cruise altitude but was busy dealing with Maintenance Control and the door open issue that I forgot about the 5G issue.