BTLE detection interval with HM-10/11

I built a BT beacon following to these instructions. I failed multiple times with HM-10 modules, of which non seems to be original - they did not enter sleep moder and stayed at 8mA -, but got it working with an HM-11.

What I observered in all cases, however, is that my OP3 with "Beacon Scanner" app only gets a signal every 24-25 seconds.
Using my uCurrent, I can see that the device wakes up every 5xx ms, as described in the PDF, though. Even the ones that kept drawing 8mA without sleeping showed this behavior. Can anybody explain why the update interval is so low? If I wanted to use the proximity feature for searching the beacon, this would be quite annoying.
I would have expected to get an update every 5xx ms.