Air carrier Captain reported autopilot issues on final approach at DCA; citing 5G interference as possibly contributing.

Narrative

The flight to DCA was uneventful till about 5 miles on final. We had a constant tail wind on the approach around 30-40 kts. Approach was conducted on autopilot. We broke off around 1400-1800 ft. and continued in marginal VMC. After we passed 1000 ft. in stable conditions I noticed that aircraft slowly and then more aggressively starting to pitch down and vertical speed suddenly increasing from 800-900 ft/min to 1200-1800 ft/min. I was hoping that autopilot would correct this pitch down moment; but it didn't respond as I expected. I disconnected autopilot and stabilized path and speed before 500 ft. AGL. The rest of the of the approach and landing was uneventful. I would think that there was a combination of factors of the strong tailwind and some interference from the ground facilities. I am not sure if 5G interference played a role in this approach. I hope my case was a single event today; but if there were numerous aircraft affected on the approach this day; it should be investigated.