Rollup bugs on 7.11.0 in kibana

Hello,
I upgraded on the 7.11.0 on the elastic cloud this week.
Since then, I got new issues with my rollups.

At first the option to create an index pattern on rollups index disapeared.
Before I got this button :

Now :

And when I try to create a visualization (vertical bar chart on my tests)

I got the message:

There is not a rollup job that has a [date_histogram] agg on field [@timestamp] which also satisfies all requirements of query.

After playing with the generated request :

GET rollup_filebeat_v2/_rollup_search
{
 "aggs": {
    "2": {
      "date_histogram": {
        "field": "@timestamp",
        "fixed_interval": "120m",
        "time_zone": "Indian/Mauritius",
        "min_doc_count": 1
      }
    }
  },
  "size": 0,
  "fields": [
    {
      "field": "@timestamp",
      "format": "date_time"
    }
  ],
  "script_fields": {},
  "stored_fields": [
    "*"
  ],
  "_source": {
    "excludes": []
  },
  "query": {
    "bool": {
      "must": [],
      "filter": [
        {
          "match_all": {}
        },
        {
          "range": {
            "@timestamp": {
              "gte": "2020-11-23T14:27:15.388Z",
              "lte": "2021-02-21T14:27:15.388Z",
              "format": "strict_date_optional_time"
            }
          }
        }
      ],
      "should": [],
      "must_not": []
    }
  }
}

But it works if I remove the timezone:

GET rollup_filebeat_v2/_rollup_search
 {
   "aggs": {
     "2": {
       "date_histogram": {
         "field": "@timestamp",
         "fixed_interval": "120m",
         "min_doc_count": 1
       }
     }
   },
   "size": 0,
   "fields": [
     {
       "field": "@timestamp",
       "format": "date_time"
     }
   ],
   "script_fields": {},
   "stored_fields": [
     "*"
   ],
   "_source": {
     "excludes": []
   },
   "query": {
     "bool": {
       "must": [],
       "filter": [
         {
           "match_all": {}
         },
         {
           "range": {
             "@timestamp": {
               "gte": "2020-11-23T14:27:15.388Z",
               "lte": "2021-02-21T14:27:15.388Z",
               "format": "strict_date_optional_time"
             }
           }
         }
       ],
       "should": [],
       "must_not": []
     }
   }
 }

I did not found bug fixes annoncement on thoses features in the 7.11.1

UP, @elastic_team could you help me please ?

I finally found the solution.
It's not a bug, it's just that we can declare only one index pattern per rollup index.
So if no rollup index is available the button will not be shown.