zabbix logic for incoming values and integer target items is as follows :

• if an incoming value is an integer but we end up with a decimal part as a result of the internal calculations (multiplier, store value), we trim the decimal part and store the result;
• if an incoming value is a decimal, the item turns unsupported

that's not the case with ipmi items - if an ipmi item has an incoming decimal value, it is silently trimmed and the result is stored.
instead, the item should turn unsupported