[Bug]: Exception in browsergym make it unusable thereafter

Is there an existing issue for the same bug?

[X] I have checked the troubleshooting document at https://docs.all-hands.dev/modules/usage/troubleshooting
[X] I have checked the existing issues.

Describe the bug

During a BrowsingAgent web search an exception occured: raise MarkingError("Cannot mark a child frame without a bid.")

From then on, attempts to browse further failed with e.g.

    |10:19:29 - openhands:DEBUG: client.py:351 - Action output:
    |**BrowserOutputObservation**
    |URL:
    |Error: True
    |Open pages: []
    |Active page index: -1
    |Last browser action:
    |Last browser action error: Browser environment took too long to respond.
    |Focused element bid:
    |axTree: {}
    |CONTENT: Browser environment took too long to respond.

Current OpenHands version

main (current source)

Installation and Configuration

make build and run, run, run!

Model and Agent

Sonnet 3.5, CodeActAgent -> BrowsingAgent

Operating System

WSL

Reproduction Steps

idk, as it couldn't get past Google's cookie consent form (in German language) it tried to search another site

Logs, Errors, Screenshots, and Additional Context

10:18:19 - openhands:DEBUG: client.py:349 - Running action:
    |**BrowseInteractiveAction**
    |THOUGHT: I understand that we need to start our search for information about polar bear population estimates. Since we don't have a current page or accessibility tree to work with, we need to navigate to a reliable source for this information. Let's start by going to the World Wildlife Fund (WWF) website, which is a reputable conservation organization that often provides up-to-date information on endangered species.
    |
    |To accomplish this, I will use the goto action to navigate to the WWF website:
    |
    |In order to begin our search for polar bear population estimates, we need to visit a reliable conservation website.
    |BROWSER_ACTIONS: goto("https://www.worldwildlife.org/")
    |Process Process-1:
    |Traceback (most recent call last):
    |  File "/openhands/miniforge3/lib/python3.11/multiprocessing/process.py", line 314, in _bootstrap
    |    self.run()
    |  File "/openhands/miniforge3/lib/python3.11/multiprocessing/process.py", line 108, in run
    |    self._target(*self._args, **self._kwargs)
    |  File "/openhands/code/openhands/runtime/browser/browser_env.py", line 133, in browser_process
    |    obs, reward, terminated, truncated, info = env.step(action)
    |                                               ^^^^^^^^^^^^^^^^
    |  File "/openhands/poetry/openhands-ai-5O4_aCHf-py3.11/lib/python3.11/site-packages/gymnasium/wrappers/order_enforcing.py", line 56, in step
    |    return self.env.step(action)
    |           ^^^^^^^^^^^^^^^^^^^^^
    |  File "/openhands/poetry/openhands-ai-5O4_aCHf-py3.11/lib/python3.11/site-packages/browsergym/core/env.py", line 389, in step
    |    obs = self._get_obs()
    |          ^^^^^^^^^^^^^^^
    |  File "/openhands/poetry/openhands-ai-5O4_aCHf-py3.11/lib/python3.11/site-packages/browsergym/core/env.py", line 505, in _get_obs
    |    raise e
    |  File "/openhands/poetry/openhands-ai-5O4_aCHf-py3.11/lib/python3.11/site-packages/browsergym/core/env.py", line 481, in _get_obs
    |    _pre_extract(self.page, self.tags_to_mark)
    |  File "/openhands/poetry/openhands-ai-5O4_aCHf-py3.11/lib/python3.11/site-packages/browsergym/core/observation.py", line 73, in _pre_extract
    |    mark_frames_recursive(page.main_frame, frame_bid="")
    |  File "/openhands/poetry/openhands-ai-5O4_aCHf-py3.11/lib/python3.11/site-packages/browsergym/core/observation.py", line 69, in mark_frames_recursive
    |    raise MarkingError("Cannot mark a child frame without a bid.")
    |browsergym.core.observation.MarkingError: Cannot mark a child frame without a bid.
    |10:18:49 - openhands:DEBUG: client.py:351 - Action output:
    |**BrowserOutputObservation**
    |URL:
    |Error: True
    |Open pages: []
    |Active page index: -1
    |Last browser action:
    |Last browser action error: Browser environment took too long to respond.
    |Focused element bid:
    |axTree: {}
    |CONTENT: Browser environment took too long to respond.
    |

All-Hands-AI / OpenHands

[Bug]: Exception in browsergym make it unusable thereafter #3944