Can not add some snaps to map?

I have MindManager 21 and Snap on both Windows and Android.

All works ok, snaps from PC or phone get to queue but then, only occasionally, I can not add the Snap to any map.

Dragging from the queue to map appears to make a topic, the blue 'dropping here' ghost shows on the map, but the topic is never created. Have tried on a new map, from basic template, but makes no difference. Also happens to snaps from either Edge or MindManager app on phone.

Not a big deal as can quick view the snap and copy paste content to map, but odd.

Have tried restarting machine, logging out/in etc but makes no difference. Anybody else had this?