AR Step record behavior. bug?

Step Rec: Standard (REC+STOP) places the trig, then advances the green trig NOT to the very next step but rather to the step after that i.e. skips a step!
Standard should not to be confused with Step Rec: Jump, which respects the trig LEN parameter.

So far I have not found any indication that this is the intended behavior, and it differs from what the manual says and how other Elektron I have gear works.

Any thoughts? known bug? ancient bug or recent version bug? NEW bug?

PS have not yet upgraded to 172