I was playing on a Realm when I initiated a raid. I cleared the first wave, as well as a few mobs from a second wave. I realized the Raid progress bar was 3/4 full, yet I didn't see any Illagers.

Since I have a Nether portal near by, I entered it to find a couple Vindicators & a Pillager. I killed them in the Nether, then returned to find the Raid progress bar had disappeared. When I tried interacting with villagers, I was unable to trade with them; presumably they were locked due to the Raid. I re-logged to see if that would fix anything.

When I got back on, the Raid progress bar returned, yet there is no way for me to continue with the Raid.

Edit: The Raid seems to have expired on it's own after a while.