Flying spark today and lost connection with controller. Spark was preparing himself to return to homepoint as i received this error. Spark was almost 300 meters from homepoint.

But drone ignored message and came luckily back.

For info. No interferences , no error messages before take off , had plenty of satelites, open field,homepoint recorded.

Error message makes no sence to me as spark was already beyond 50 m distance and 30m heigh.

Maybe dji should fix this soon with new bugfix update.
Or has someone a explanation?

I've never seen that one.  Yes it could be a bug, but another factor is the phone itself.  iphones are pretty stable, androids can be a challenge.  I have all kinds of "interesting" behavior occur on my android which usually is resolved by a reboot.  Not saying that this is your issue, but it's worth trying a reboot and trying to repeat this occurrence.

I was using an iphone 7 plus, usually ipad mini 4 but left this home.
I was using controller with otg cable , this is usually 2.4 ghz. But noticed upon landing that i left wifiband flightmodus on. Wifi was from controller and was 5.8 ghz. Maybe that was conficting

After landing i switched off spark, turn it on again and it ad no issues, went further than 50 m and higher than 30 m. It must be a bug.

Dji? Please bugfix this

Restart the APP, this prompt will disappear, we'll forward it to our engineers, will optimize it in the next update.