Steps to reproduce:

1. create host > item > select type "SNMP v2 agent" / Key&OID  hrStorageSize.1&.1.3.6.1.2.1.25.2.3.1.5.1 / Unit = kb. Screen = 1
2. Go to Monitoring > Latest data  select host and our item.
   The result is  4Mkb  Screen = 2
3. In fact we have value
   snmpwalk -v 2c -c public 10.110.2.46 1.3.6.1.2.1.25.2.3.1.5.1
   HOST-RESOURCES-MIB::hrStorageSize.1 = INTEGER: 4040024 (4GB RAM)
4. If change Unit = Kb to b/Gb  or another it willbe seen like Mb / MMb / MGb

The same problem with network interfaces

Screen = 3-4