Schedule not working with phone hotspot

Like many others I have no wifi router, so I followed this guide to connect my bulb to my phone, and it seemed to be working fine at first.

However, I’m having issues with the schedules. From what I can tell, they work (although about half a minute late) when I have the app opened or I use my laptop as a hotspot and connect both the phone and the bulb to that. But when I use the phone’s hotspot and lock the phone… nothing.

At first I thought maybe the hotspot is deactivated, but I connected my laptop to it and had internet access (even with the phone locked). I looked through the forum but couldn’t find anything. Has anybody had the same issue, or does anyone have any idea what the problem might be?

If network traffic between bulb and your phone hotspot, it makes no scenes that Schedule doesn’t work.

Please make sure if you can control bulb with another phone when you lock your phone with hotspots.