With the Android-Settings for Oruxmaps "Keep app running in background" and "Ignore battery optomisation" and choosing "FUSED LOCATION PROVIDER" in Orux, track recording stopped still after a few minutes. Then I put the widget on one of my screens as olwaldi wrote on Mon Jul 02, 2018 7:39 am. Thereafter also with my device (Honor 9, Android 8.0.0, Oruxmaps v.7.2.14) track recording worked in my one-hour test perfectly.
Thanks to olwaldi for the tip and to Orux for the great app
Regards, Fritz