Tactix 7 pro step count / stair limit vibration

Coming from a Tactix delta  to a 7 Pro solar. On the Delta when I reached my step count / stair count limit I'd get a very definite continuous buzz from the vibration motor to notify me I'd reached the step limit / stair count limit. 

On the 7 Pro solar when I reach these limits I get a buzz buz buz like getting hit on the wrist by a dying flie. The vibrations seems to start ok then fizzle out. 

Can I please ask what anyone else's experience is with the haptic feedback is at these limits on the 7 pro ? is my device faulty...

Thank you.