That issue is known. Update LS3 to the release from today and check again.
Fixed issue #16346: File Upload modal not working correctly in latest Chromium 83.0.4103.61
I tried and I don't think I succeeded. I am not very familiar with the upload question type, so I don't really know what they result should look like. But I see this, when I try to upload a PDF file:
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Provide your LS version and where it is installed (own server, uni/employer, SaaS hosting, etc.).
Always provide a LSS file (not LSQ or LSG).
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