Powershell Remote Copy fails, locally it works - powershell

Question

We have logfile on a server A in a different location (no UNC Path access) and we wish to copy the file to server B. This successfully works with Copy-Item -FromSession (run on Server B) as long as the file is closed. So we can successfully copy the previous day's logs but not today's.
$cred = Get-OurUserCredentials
$sess = New-PSSession -ComputerName $ServerA -Credential $cred -Authentication Negotiate
$LogFile = "D:\log\tomcat\access.20180227.log"
Copy-Item -FromSession $sess $LogFile "D:\logs\tomcat\" -Force
However, we can locally copy the active log of today if we run Copy-Item locally on server A. It's only Copy-Item -FromSession on server B which fails with:
Copy-Item : The process cannot access the file 'D:\log\tomcat\access.20180227.log' because it is being used by another process.
At line:11 char:2
As a workaround we could create a local task on server A to create a local copy but why is this necessary?
Why does Copy-Item behave differently when run remotely and can we "fix" it's behaviour so it copies the log remotely as it would locally.

Answer 1

A version of the answer proposed in the OP but avoiding the need for a scheduled task.
$cred = Get-OurUserCredentials
$sess = New-PSSession -ComputerName $ServerA -Credential $cred -Authentication Negotiate
#ScriptBlock to copy file locally
$SB =
{
#Create variables on the remote machine avoid havin gto pass to scriptblock
$LogFile = "D:\log\tomcat\access.20180227.log"
$TempDes = "temporarylocationhere"
Copy-Item -Path $LogFile -Destination $Des
}
#optional scriptblock to clean up
$SB2 =
{
Remove-Item -Path $TempDes -force
}
#Run the copy file scriptblock
Invoke-Command -Session $sess -ScriptBlock $SB
#Copy file
Copy-Item -FromSession $sess $TempDes "D:\logs\tomcat\" -Force #"
#Run clean up scriptblock
Invoke-Command -Session $sess -ScriptBlock $SB2

Answer 2

Have you considered using a PSDrive to map the remote location and then copy the file to or from that drive?
The New-PSDrive cmdlet creates temporary and persistent drives that
are mapped to or associated with a location in a data store, such as a
network drive, a directory on the local computer, or a registry key,
and persistent Windows mapped network drives that are associated with
a file system location on a remote computer.
Example using your code:
# Change the ServerNameToCopyTo below
New-PSDrive -Name "Remote" -PSProvider "FileSystem" -Root "\\ServerNameToCopyTo\log\tomcat\"
$LogFile = "D:\log\tomcat\access.20180227.log"
Copy-Item $LogFile "Remote:\" -Force