Use AWS Get-EC2PasswordData from embedded credentials custom script

I'm trying to dynamically obtain the password for an AWS EC2 instance using the Get-EC2PasswordData powershell cmdlet. I have

$Result.Username = "administrator"
$Result.Domain = ""
$Result.Password = Get-EC2PasswordData -InstanceId i-0123456789 -PemFile $env:USERPROFILE\.aws\MyKey.pem

Running this via powershell session works fine, however, when I even try to save this entry, I get:

Could not load type 'Amazon.Runtime.CredentialManagement.CredentialProfileStoreChain' from assembly 'AWSSDK.Core, Version=3.3.0.0, Culture=neutral, PublicKeyToken=885c28607f98e604'.
At line:13 char:20
+ ... .Password = Get-EC2PasswordData -InstanceId i-0123456789 -PemFile $en ...
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo: NotSpecified: (:) [Get-EC2PasswordData], TypeLoadException

I have AWS PowerShell 3.3.428.0 installed. I added GET-AWSPowerShellVersion to my credentials script (the output from it is included in the error dialog) and it shows the same.

I also noticed that when RemoteDesktopManager.exe starts up, there are many assembly binding errors for AWSSDK items (via fuslogvw):



These all look the same:


*** Assembly Binder Log Entry (2/6/2019 @ 9:01:15 PM) ***

The operation failed.
Bind result: hr = 0x80070002. The system cannot find the file specified.

Assembly manager loaded from: C:\Windows\Microsoft.NET\Framework\v4.0.30319\clr.dll
Running under executable C:\Program Files (x86)\Devolutions\Remote Desktop Manager\RemoteDesktopManager.exe
--- A detailed error log follows.

=== Pre-bind state information ===
LOG: DisplayName = AWSSDK.SecretsManager
(Partial)
WRN: Partial binding information was supplied for an assembly:
WRN: Assembly Name: AWSSDK.SecretsManager | Domain ID: 1
WRN: A partial bind occurs when only part of the assembly display name is provided.
WRN: This might result in the binder loading an incorrect assembly.
WRN: It is recommended to provide a fully specified textual identity for the assembly,
WRN: that consists of the simple name, version, culture, and public key token.
WRN: See whitepaper http://go.microsoft.com/fwlink/?LinkId=109270 for more information and common solutions to this issue.
LOG: Appbase = file:///C:/Program Files (x86)/Devolutions/Remote Desktop Manager/
LOG: Initial PrivatePath = NULL
LOG: Dynamic Base = NULL
LOG: Cache Base = NULL
LOG: AppName = RemoteDesktopManager.exe
Calling assembly : System.Management.Automation, Version=3.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35.
===
LOG: This bind starts in default load context.
LOG: Using application configuration file: C:\Program Files (x86)\Devolutions\Remote Desktop Manager\RemoteDesktopManager.exe.Config
LOG: Using host configuration file:
LOG: Using machine configuration file from C:\Windows\Microsoft.NET\Framework\v4.0.30319\config\machine.config.
LOG: Policy not being applied to reference at this time (private, custom, partial, or location-based assembly bind).
LOG: Attempting download of new URL file:///C:/Program Files (x86)/Devolutions/Remote Desktop Manager/AWSSDK.SecretsManager.DLL.
LOG: Attempting download of new URL file:///C:/Program Files (x86)/Devolutions/Remote Desktop Manager/AWSSDK.SecretsManager/AWSSDK.SecretsManager.DLL.
LOG: Attempting download of new URL file:///C:/Program Files (x86)/Devolutions/Remote Desktop Manager/AWSSDK.SecretsManager.EXE.
LOG: Attempting download of new URL file:///C:/Program Files (x86)/Devolutions/Remote Desktop Manager/AWSSDK.SecretsManager/AWSSDK.SecretsManager.EXE.
LOG: All probing URLs attempted and failed.



I also noticed Remote DesktopManager ships with AWSSDK 3.3.8.0 dlls (Core, EC2 and S3), and I suspect this is probably related.

Is there a way I can run Get-EC2PasswordData for a custom credentials script? Or another workaround that would let me do this?