This is normal. Push/Pull is bumping into other geometry that is in the same context as the surface you are moving. If you have not noticed this in the past it is because the object you were push/pulling past was in a separate context, ie it was contained in a separate group or component. If the obstruction is contained in it’s own component or group then it is not seen as an obstacle because the two surfaces are not in the same context.
You can tell if an object is has been made a group or component by clicking on it and seeing if it has a bounding box. Best practice is to make groups or components out of all separate pieces of your model.
