While following up on #7663 (comment), I noticed that the task stream plot on the dashboard is sporadically broken when using the main branch of distributed (it appears okay when using the latest release).

With bokeh=2.4.3 and dask + distributed main I ran the following little snippet locally

import time

from dask import delayed
from dask.distributed import Client, wait, performance_report

@delayed
def inc(x):
    time.sleep(0.1)
    return x + 1

@delayed
def double(x):
    time.sleep(0.1)
    return 2 * x

@delayed
def add(x, y):
    time.sleep(0.1)
    return x + y

if __name__ == "__main__":
    with Client(n_workers=4, threads_per_worker=2, memory_limit="4 GiB") as client:
        print(f"{client.dashboard_link = }")
        with performance_report():
            data = list(range(500))
            output = []
            for x in data:
                a = inc(x)
                b = double(x)
                c = add(a, b)
                output.append(c)

            total = delayed(sum)(output)
            total = total.persist()
            wait(total)
            del total

While that script is running, I navigate to the dashboard link in my browser (have used Firefox, Safari, and Chrome). Frequently, maybe 60% of the time?, the task stream is broken and looks like this

Sometimes it's not broken, but becomes broken if I refresh the dashboard page enough.

Are others able to reproduce this same behavior?

Manually going through commits in the distributed git history since the last release, it looks like #7586 is where things appear to start breaking. But looking through that PR I don't see anything that looks obviously related.