Metal-on-metal rasping cicada-like noise

Hi everyone,
Anyone ever run into this kind of noise?
2013 Prius+ (Prius v for USA/Canada)

When I accelerate gently while on the gas engine, I often get this weird metal-on-metal rasping / grinding noise a bit like a metal cicada or like a saw against a metal bar. Goes grinn-grinn-grinn, sometimes once, sometimes a few times in a row.

Toyota said everything looked fine at service. Took a mechanic out for a drive — he heard it too but had no idea. Appointment booked to dig into it.

Short recordings (hosted on my PCloud) will be posted as soon as am given permission (but I should post 4 times , so quite hopeless.)

 

Copy paste error
The message should've ended with :

"Appreciate any thoughts or ideas.
Thanks!"

 

Thx for the fast reply.
I 'll suggest the mechanic ! I'm totally dumb.
But I see no leak

 

I posted a VIDEO on YOUTUBE
You may lesten to the noise if you search Youtube for
Prius plus (v for USA/CND) noise
It comes up on top

 

Thanks for your efforts but something happened to this video . I had to convert an MP3 recording into a video to post it on Youtube and the converter added an empty track.

I had edited the sound to decrease backgroune nois and suppress parts of the recording with no event.

Yet 2 occurrences of the weird noise can be heard within those 3 seconds/