Preview in Slack is not available for Trend Questions

After applying new Metabase version 0.41.2 previews became unavailable in Slack messages.
Can you please help me understand what's happened here and how we can resolve it? Thanks!

{
  "browser-info": {
    "language": "en-US",
    "platform": "MacIntel",
    "userAgent": "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_14_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/96.0.4664.55 Safari/537.36",
    "vendor": "Google Inc."
  },
  "system-info": {
    "file.encoding": "UTF-8",
    "java.runtime.name": "OpenJDK Runtime Environment",
    "java.runtime.version": "11.0.13+8",
    "java.vendor": "Eclipse Adoptium",
    "java.vendor.url": "https://adoptium.net/",
    "java.version": "11.0.13",
    "java.vm.name": "OpenJDK 64-Bit Server VM",
    "java.vm.version": "11.0.13+8",
    "os.name": "Linux",
    "os.version": "5.4.149-73.259.amzn2.x86_64",
    "user.language": "en",
    "user.timezone": "UTC"
  },
  "metabase-info": {
    "databases": [
      "postgres",
      "snowflake"
    ],
    "hosting-env": "unknown",
    "application-database": "postgres",
    "application-database-details": {
      "database": {
        "name": "PostgreSQL",
        "version": "10.17"
      },
      "jdbc-driver": {
        "name": "PostgreSQL JDBC Driver",
        "version": "42.2.23"
      }
    },
    "run-mode": "prod",
    "version": {
      "date": "2021-11-09",
      "tag": "v0.41.2",
      "branch": "release-x.41.x",
      "hash": "ad599fd"
    },
    "settings": {
      "report-timezone": "US/Eastern"
    }
  }
}

Hi @martasakal
Which version did you upgrade from?
I think there's too much getting lost in translation, can you include a screenshot of what Trend questions looks like now and how they looked before?
Check the log for errors - Admin > Troubleshooting > Logs.

Here examples of questions with/without previews. I could not find any errors in logs

@martasakal If you want to show a graph like the bottom picture, then change the visualization to Line.

It's not the same type of visualization that we had before with trends.
Also numbers are not displayed as images. (For example in New Customers - By Week)

@martasakal I don't understand. Too much information is getting redacted. Have you included the visualization "New Customers - By Week" ?

Ok, let me show you some faked numbers.
How trends question preview was looking before:


And how it looks now:
54%20AM

@martasakal I cannot reproduce. I'm getting the same numbers for the same query using different visualization.
But Trend visualization will not show a graph anymore. If you want a graph, then change the visualization to a Line.
image

Ok, but if I click on image preview it shows other graph:

57%20PM

@martasakal Okay, I'm not sure what's going on there. Perhaps it's a Slack issue? Metabase does not control what Slack does.

Can I find POST request that Metabase sends to Slack anywhere?

@martasakal The Slack requests is handled in the integration: https://github.com/metabase/metabase/blob/master/src/metabase/integrations/slack.clj#L71
We're working on redoing the entire Slack integration:
https://github.com/metabase/metabase/issues/12383