ER createEngine Cannot load the Engine without a path

This error is NOT always happening. I cant understand why it is happening.
How to resolve this error? ER createEngine Cannot load the Engine without a path

the message is shown after a very basic test on the second parameter on createEngine calls, also the check is in in a method that is never called internally (i.e. there is always a call from the API for that message to be shown).

Please check all your createEngine calls and verify that the second parameter is always a valid string