Unexpected behaviour of "Execute arbitrary PHP script" action

When introducing a "Execute arbitrary PHP script" action, the description line explicitly states :

Note that it is up to the script to save the $entity once it\'s done modifying it.

So it may be expected that the module does not save the entity...
But it does, (see related issue) which can give unexpected results, particularly if the script deletes the entity : the entity_save() then goes wild, more so if there are sophisticated hook_entity_save() attached...

There are a couple of open issues dealing with this "changes_properties" behavior being default, but I think "Execute arbitrary PHP script" should be handled separately