Measure shows different format and date value after published and refreshed in service

Hey,
I have had similar issues with dates.
I would check that in desktop the Invoice_Posting_Date is of data type 'Date'.
Check the original source data for this, is the data all in consistent date format(Use power query editor). 
I would also use power query editor to transform that column so that the format is in more standarised for a date - would get rid of '.' and the space to a '/' -
You can use transform data, go to column, under transform tab click replace values and change the period space to /

Also in power query (Click transform data in desktop) make sure that data type for that column is 'Date' - this is found under transform tab.

A few things to try, my desktop is all in english so hopefully this makes sense for hungarian too.

Let me know if any help 🙂