Using Gideros 2017.9, calling iab:requestProducts() with Google I'm getting back all the expected products except for a monthly subscription product. I don't know when that stopped working, but it was working in 2016.8.1. I also don't know if this is an issue with frameworks other than Google.
I see that IAB has been changed in recent Gideros updates. Could one of those changes have effected how the plugin handles subscriptions?