[Bug] labs.pybricks.com reports a timeout on EV3 usb connection

[BertLindeman]

Describe the bug Running a script on labs.pybricks.com on an EV3 via USB reports:

Error: Timed out waiting for response
    at https://labs.pybricks.com/static/js/main.93bad3a8.js:2:590290
    at Generator.next (<anonymous>)
    at h (https://labs.pybricks.com/static/js/main.93bad3a8.js:2:1413608)
    at l (https://labs.pybricks.com/static/js/main.93bad3a8.js:2:1413925)
    at t (https://labs.pybricks.com/static/js/main.93bad3a8.js:2:1409046)
    at l (https://labs.pybricks.com/static/js/main.93bad3a8.js:2:1413925)

To reproduce Steps to reproduce the behavior:

1. Go to labs.pybricks.com
2. Click on connect USB
3. Connect to the EV3
4. Select a tiny program (see below)
5. Click Run or press F5
6. See the timeout pop-up. The program at this point does run.

Expected behavior What did you expect to happen instead? No tineout

Screenshots There is a saying that a picture is worth a 1000 words. Screenshots really help to identify and solve problems.

Test program

from pybricks.tools import wait

print('hi')
wait(5000)

Extra info

1. Ran this with various firmware on the EV3 up to Pybricks MicroPython ci-build-4445-v4.0.0b2-5-gc2910aa2 on 2025-11-26 from ev3-firmware-build-4152-git9759e904 So I assume the problem to be in labs.pybricks.com Even with the wait deleted I get the same result.

2. Running Linux Mixt Xia and Google Chrome Version 142.0.7444.175 (Official Build) (64-bit)