If you use {{flag::##raw_data_filled##|nl2br}} in a email html notification for example, it will break if the user writes "|" into the input. It will break too, if the label of the input contains "|". The output stops by the first "|" sign.
System-Log:
Unknown insert tag flag " DE " in {{flag::Firma: Verein | DE |nl2br}} on page https://***/
Verein | DE was the user input.
Ofcourse I can remove the "|" characters from the label, but without further ado I can't prevent "|" is used by the user.
Tested with:
Contao 4.13.15
Notification Center: 1.7.1
Haste: 5.0.16