Steps to reproduce:

1. Create a discovery rule and itemprototype as either a numeric or float type
2. Create a usermacro of any name you like and set it with a valid zabbix time unit suffix value (i.e. '3d')
3. For the itemprototype created set the history storage period value to the name of the usermacro
4. Populate values for the itemprototype (perform LLD, send metrics, etc) so that data is available in the frontend
5. Once data is available create a new dashboard. In the dashboard choose the 'Graph' widget.
6. In the graph widget I wildcarded the host value and the item value, but this is reproducible if you specify the exact name of the item that is created from the prototype. Once you specify the item an error shows at the top of the widget "Incorrect value for field "history": invalid history storage period."

Expected:

1. I would expect the usermacro to be resolved. This worked in version 5.4.10