Are there any known limitations or issues when printing webmaps containing Subtype Group Layers?

In general there are no known limitations when printing Subtype Group Layers (SGL) with the VertiGIS Printing Engine (VSPE). However there is a known issue for VSPE deployments on ArcGIS Enterprise 11.4 or lower. VertiGIS Studio Web (and other modern web clients) are using ArcGIS Java Script 4.x API, based on Authorization Code Flow oAuth2 Access Tokens. This authentication mechanism refreshes the access token for the ArcGIS Portal frequently in 30 min. intervals by default, to keep the user authenticated during longer web sessions. This also means that new access tokens for accessing protected SGLs are sent to the VSPE as part of the print request. This renewed access token however causes missing content of SGLs on printouts, both for the user who triggered the print and potential for any other portal user. The issue occurs potentially for any subsequent print request and can only be recovered by restarting the VSPE on the federated ArcGIS Server, or by configuration of short-living worker instances for the VSPE (not recommended for production). To overcome this issue use ArcGIS Enterprise 11.5 or higher.