Getting same error. Probably worth creating simplified example with simple scene to replicate a problem. Error message is null which I’ve never seen. Does this misbehave in any browser?
From my experience, Chrome can’t reliably create more than a few WebGL contexts reliably (assuming you’re loading a bunch of assets). This is a browser issue rather than a PlayCanvas issue, Might be worth creating a simple repro and logging it here.
To implement bots, I would suggest creating headless node code, that would connect like a browser to your servers, and simulate gameplay, but need no rendering. This would allow you to spin multiple bots without a trouble, and even automate this process, which could allow you even stress-test your servers.