Question about Stx Valve Adapter Kit

I use the kit for the Bravo BTP 12 (item 17275577), which has a screw connection (in the picture above with the red ring) for inflatable boats and SUPs, in order to be able to inflate other inflatable items (air mattress / bathing island) with it. The adapter fits onto this screw connection.

We used the kit on 2 SUP pumps and it went okay 1x and fine the other time.