So, the only difference being the case, you're saying? PowerShell's generally case-insensitive, but anytime you use a -Filter, the shell is just handing off to the underlying technology, which might be case-sensitive.
FWIW, both commands run without error on my Win2012R2 system, so it's possible 2008R2 was case-sensitive. The PowerShell v3 docs would likely have been written from Win2012 behavior.
I just ran into this exact same issue. Code I had written that used "LogName" which worked fine on some boxes failed when I attempted to run them remotely using InvokeCommand with the same error the OP mentioned. When I changed my code to read "logname" (all lowercase) it functioned as expected.