IMHO I’m on the same error ([Transformation JavaScript] Getting an error after moving to openHAB 2.5.6~S147-1 (Build #147))
RasPI 3B / openHABian installation
openjdk version "1.8.0_252"
OpenJDK Runtime Environment (Zulu 8.46.0.225-CA-linux_aarch32hf) (build 1.8.0_252-b225)
OpenJDK Client VM (Zulu 8.46.0.225-CA-linux_aarch32hf) (build 25.252-b225, mixed mode, Evaluation)
Additionally this topic is also caused by a JavaScript failure.