I see this happens in Power Civil South Africa SS4 as well as the latest version of Open Roads Designer EAP
When you draw a curve return for an intersection with an ahead taper on a straight line the taper criteria is honored as per the image below
No the same taper but from the curve return
The intersection is shifted to the inside of a horizontal curve and you can see that the taper with its rules
Now below you can see the ahead tapers rule is not honored:
Although it states the rule it does not match the stand alone offset taper.
The same was replicated in OR-EAP