Are you @mocelet using in both cases SmartThings Lighting group (or individual lights)?
Edit:
I did some tests.
Lighting group execution location is local.
Simple ST App routines and RulesAPI rules involving Lighting group are executed locally. More complex RulesAPI rules involving Lighting group are executed in the cloud.
In my opinion, all group routines used to be cloud-based.
Edit 2:
If Lighting group is used as a condition, the RulesAPI rule becomes cloud-based.
