Error when attempting to connect to SSH session via Warpgate

I have recently deployed warpgate for centralising SSH sessions and additional security for my public facing services. I would like to be able to use RDM to connect to my SSH endpoints behind warpgate.
When creating the endpoints within the warpgate interface, the username for the session is automatically generated using the following schema
name:target@warpgatefqdn - for example: adrian:server@warpgate.contoso.com

Using Powershell, or any other shell that uses an OpenSSH client to connect, I am able to easily connect through to my endpoints.

However, when using RDM, I get the following message:
ArgumentOutOfRangeException - length ('-6') must be a non-negative value. (Parameter 'length')
Actual value was -6.

at System.ArgumentOutOfRangeException.ThrowNegative[T](T value, String paramName)
at System.ArgumentOutOfRangeException.ThrowIfNegative[T](T value, String paramName)
at System.String.ThrowSubstringArgumentOutOfRange(Int32 startIndex, Int32 length)
at System.String.Substring(Int32 startIndex, Int32 length)
at Devolutions.Protocols.SshDestination.FromSshCreds(String user, String host, Int32 port)
at Devolutions.Protocols.XtermSsh.Connect()
at Devolutions.RemoteDesktopManager.Frames.Embedded.FreEmbeddedNativeSshShell.Connect()
at Devolutions.RemoteDesktopManager.Managers.EmbeddedViewManager.OpenEmbedded(FreEmbeddedView frame, Connection connection, Boolean isConnected, OpenConnectionMode openConnectionMode, Image image, Image imageLarge, String svgName, Nullable`1 imagePaletteType)
at Devolutions.RemoteDesktopManager.Managers.EmbeddedViewManager.Open(Connection connection, FreEmbeddedView frame, Boolean isConnected, OpenConnectionMode openConnectionMode, Boolean undocked, Image image, Image imageLarge, String svgName, Nullable`1 imagePaletteType)
at Devolutions.RemoteDesktopManager.Business.Connectors.EmbeddedConnector.Connect(Connection connection, OpenConnectionMode openConnectionMode)
at Devolutions.RemoteDesktopManager.Managers.ConnectionManager.OpenConnection(Connection connection, OpenConnectionParameter parameter)
at Devolutions.RemoteDesktopManager.Managers.ConnectionManager.OpenConnections(Connection[] connectionList, OpenConnectionParameter parameter)
at Devolutions.RemoteDesktopManager.Managers.ActionManager.DoOpenConnection(Connection[] currentConnections, OpenConnectionMode openConnectionMode, IConnectionSource source, Dictionary`2 openingAttributes, Boolean reconnecting)
at Devolutions.RemoteDesktopManager.Managers.ActionManager.OpenConnections(OpenConnectionMode openConnectionMode, IConnectionSource source, Boolean checkOpenedConnection)
at Devolutions.RemoteDesktopManager.Managers.SessionMenuManager.MnuOpenConnection_Click(Object sender, EventArgs e)
at Devolutions.RemoteDesktopManager.Controls.EnhancedBarButtonItem.OnClick(BarItemLink link)
at DevExpress.XtraBars.BarItem.PerformClick(BarItemLink link)
at DevExpress.XtraBars.BarItem.PerformClick()
at Devolutions.RemoteDesktopManager.Frames.FreDashBoardBase.GalleryActions_ItemClick(Object sender, GalleryItemClickEventArgs e)
at DevExpress.XtraBars.Ribbon.Gallery.BaseGallery.RaiseItemClickEvent(RibbonGalleryBarItemLink inRibbonGalleryLink, BaseGallery gallery, GalleryItem item)
at DevExpress.XtraBars.Ribbon.Gallery.BaseGallery.OnItemClick(RibbonGalleryBarItemLink inRibbonGalleryLink, BaseGallery gallery, GalleryItem item)
at DevExpress.XtraBars.Ribbon.Handler.GalleryControlHandlerBase.OnUnpressItem(DXMouseEventArgs e)
at DevExpress.XtraBars.Ribbon.Handler.GalleryControlHandlerBase.OnUnpress(DXMouseEventArgs e)
at DevExpress.XtraBars.Ribbon.Handler.GalleryControlHandlerBase.OnMouseUp(DXMouseEventArgs e)
at DevExpress.XtraBars.Ribbon.Handler.GalleryControlHandler.OnMouseUp(DXMouseEventArgs e)
at DevExpress.XtraBars.Ribbon.GalleryControl.OnMouseUp(MouseEventArgs e)
at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks)
at System.Windows.Forms.Control.WndProc(Message& m)
at DevExpress.Utils.Controls.ControlBase.BaseWndProc(Message& m)
at DevExpress.XtraBars.Ribbon.GalleryControl.WndProc(Message& m)
at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
at System.Windows.Forms.NativeWindow.Callback(HWND hWnd, MessageId msg, WPARAM wparam, LPARAM lparam)
------------------------ extended stack ------------------------
at Devolutions.RemoteDesktopManager.Forms.FrmErrorMessage.ShowErrorMessage(Exception exception, String message, String title)
at Devolutions.RemoteDesktopManager.Forms.FrmErrorMessage.ShowErrorMessage(Exception exception, String title)
at Devolutions.RemoteDesktopManager.Managers.LogManager.OnThreadException(Object sender, ThreadExceptionEventArgs t)
at System.Windows.Forms.Application.ThreadContext.OnThreadException(Exception ex)
at System.Windows.Forms.NativeWindow.Callback(HWND hWnd, MessageId msg, WPARAM wparam, LPARAM lparam)
at DevExpress.Utils.Drawing.Helpers.NativeMethods.UnsafeNativeMethods.DefSubclassProc(IntPtr hWnd, IntPtr Msg, IntPtr wParam, IntPtr lParam)
at DevExpress.Utils.Drawing.Helpers.NativeMethods.UnsafeNativeMethods.DefSubclassProc(IntPtr hWnd, IntPtr Msg, IntPtr wParam, IntPtr lParam)
at DevExpress.Utils.Drawing.Helpers.Win32SubclasserFactory.Win32Subclasser.SubClassProcInner(IntPtr hWnd, IntPtr Msg, IntPtr wParam, IntPtr lParam, IntPtr uIdSubclass, IntPtr dwRefData)
at Windows.Win32.PInvoke.DispatchMessage(MSG* lpMsg)
at System.Windows.Forms.Application.ComponentManager.Microsoft.Office.IMsoComponentManager.FPushMessageLoop(UIntPtr dwComponentID, msoloop uReason, Void* pvLoopData)
at System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(msoloop reason, ApplicationContext context)
at System.Windows.Forms.Application.ThreadContext.RunMessageLoop(msoloop reason, ApplicationContext context)
at Devolutions.RemoteDesktopManager.Program.Main(String[] args)
(Apologies for the wall of text!)

I've made multiple attempts to see if the issue is related to username (hence the references to it above), but no matter the length of username/placement of the colon (:) it seems not to make a difference with the error.

Does anyone have any ideas on what might be causing the issue?