That's wild. On April 23, KB5057056 installed on one of my computers where the jumplists had continued working after the April 8 updates. During the afternoon of April 24, I noticed that the computer seemed to be running a bit slow, so I rebooted it (the machine is normally on 24/7). This afternoon, I realized that the jumplists were broken on that computer. I'm not sure exactly when the jumplists broke on that machine since I don't use them on that machine every day, but it's likely that they broke in the last week.
As of now, 2 of my 5 Windows 10 machines have broken jumplists. One broke on April 8 (I used the jumplists on that machine daily, so I noticed it quickly), and the other broke in the last week. Both of the broken machines are used every day and remain on 24/7. The 3 that don't have broken jumplists are rarely powered on. I probably won't turn them on again until the May Cumulative Updates are available.