SDKBOX, Admob Adaptive Banner not showing

As per the SDKBOX release note 2.6.0.0 (2020.03.06), Admob Adaptive banner is supported but when I tried it doesn’t appear.

AdMob: support adaptive banner (width=-1, height=-1)

As per the Release Note value of width and height is to be kept -1 for Adaptive banner but it’s not showing the ad. If I change -1 value to 0 (smart banner) then it shows up.

Have any one tried it already ?

plz create a new banner to test it.

there is a message with

callback.

Yes I have added the listener, no messages, no banner ad, nothing happens. I tried with new banner ad unit too.
With the 0 value (smart banner) it’s working, banner is showing.
It’s really strange and kind of frustrating.