As stated in the comments on the question, 32-bit processes cannot access modules of 64-bit processes, so you cannot use your command as-is from 32-bit PowerShell if the target process is a 64-bit process.
In fact, if you try to access a 64-bit Windows PowerShell instance from a 32-bit one with your command, you get an explicit error message to that effect, at least on Windows 10 with Windows PowerShell v5.1:
A 32 bit processes cannot access modules of a 64 bit process.
As a suboptimal workaround, you can invoke 64-bit Windows PowerShell via its CLI (powershell.exe) from your 32-bit instance:
$ps64 = "$($PSHOME -replace '\\SysWOW64\\', '\\SysNative\\')\powershell.exe"
& $ps64 -noprofile { (Get-Process -Id 1468 | Select-Object -ExpandProperty Modules) }
The workaround is suboptimal in two respects:
It involves creation of a new PowerShell instance in a new process, which is slow.
More importantly, the objects that are returned are only approximations of the System.Diagnostics.ProcessModule instances that direct invocation would return.
Specifically, they are [pscustomobject] instances - with a type name of Deserialized.System.Diagnostics.ProcessModule to indicate their source - that have properties of the same names as the original objects, with static copies of their values (which may themselves be such [pscustomobject] instances; also, these instances lack the methods that the original objects have.
That said, if all you need is to access properties such as .ModuleName or .FileName, you shouldn't have a problem.
