After publishing, web refresh instant fails

Just a final update on the matter and some opinions.

tl;dr we had to add a transformation to all of our dates ( they were fine before )

We contacted MS Contact Support for help ( we actually opened 2 concurrent tickets because we were desparate ).

• The solution came after a week and a half of exchanging emails and screen sharing. One attendant knew that was something wrong with dates ( is this a undisclosed bug??? ) and got the query as soon as the MS engineers found one. The other attendant didn't know anything about anything and tried several solutions, mostly involving deleting stuff and putting it back.
  
  Here is the Query
  

  #"NewStep"=  Table.TransformColumns(
          #"Removed Columns",
              List.Transform(
                  Table.ColumnsOfType(#"Removed Columns", {type date, type nullable date, type datetime, type nullable datetime, type datetimezone, type nullable datetimezone})
                      , (name) => {name, (date) => if date = null or Date.Year(date) < 101 then null else date, Type.TableColumn(Value.Type(#"Removed Columns"), name)}
              )
          )
  in
      #"NewStep"

• No information was transparent at any moment in time
• The error message changed during our tests with no changes made ( I guess engineers changed the message, but no release notes whatsoever on that )
• We got no clue what to do, or that the problem was with our side or MS side ( only in the end we got a hot fix solution )

Felt the need to share the experience, good or bad. I hope PowerBI becomes more transparent on whats wrong.