In our roundup installations I now use CSS "word-break: break-word;" in table.messages_content, so even messages with very long words (e.g. base64 encoded strings in pasted URLs, one example are Zoom invitation links ... but long lines of underscores will exhibit this, too) will not cause trouble with the readability of other messages.

To show the issue (and maybe at some point the fix), here is such a long line of underscores:
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