Looks like the current version of R-ArcGIS bridge (v1.0.1.229) is not compatible with latest release of R (3.5). I got an error when attempted to bind the R-ArcGIS library in R-Studio. No issues enabling R ArcGIS package in ArcGIS Pro (2.1).
Installed older version of R (3.3.2) and configured R-Studio to use older version instead of default current version to resolve issue.