Thank you for your feedback on this issue. According to our policy, I can't test with the chromium you mentioned, but in Chrome, Edge, IE, OOS works fine.
Based on your description, I think you may have found the real reason, and it seems that the only solution so far is to use a different browser.
As you know, the latest OOS version so far is November 2018.
You can follow this website below, once Microsoft has the latest version, this page will be updated:
Office Online Server release schedule
You can also make calls based on your region, give feedback to Microsoft engineers, and submit your comments.
Global Customer Service phone numbers
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