v$asm_disk and v$asm_diskgroup return different results depending on who you connect as

Database version 10gR2

Host: OEL 5

Two users: one is Oracle User (oracle), and other one is non-Oracle user in OINSTALL and OSDBA group (delegate).

Database Storage: ASM (orcl)

The ownership of all the related disks is oracle:OSDBA.

If we connect to the database (orcl) as oracle, the query for v$asm_disk and v$asm_diskgroup return the correct results;

If we connect to the same database (orcl) as delegate, the same query returns empty result.

But if we connect to +ASM instance, all users can get the correct results.

And I find that GRID and ORACLE homes are the same on this host, is it a possible reason? Is it common to install the grid infrastructure software and database software together for 10gR2?