Add a new starting and a new ending point to lengthen a line feature

ForstrevierHardwaldUmgebung

Hello!

In Field Maps I have to lengthen an existing line feature: I want to add a new starting and a new ending point additionally to the existing starting and ending points.

At the ending point it works (Screenshot 1 + 2): There's a new ending point added to the "old ending point". At the starting point it doesn't work: There's a point added between the starting point and the point after it (Screenshot 3 + 4). 

How can I add a new point as in Screenshot 1 + 2 at the starting point? 

Thanks in advance!

Screenshot_2_Field Maps.jpg

Screenshot_1_Field Maps.jpg

Screenshot_3_Field Maps.jpg

Screenshot_4_Field Maps.jpg

DavidHooper_0-1741477378132.png

BarryNorthey_0-1741453512158.png

akaradimas_1-1741394043712.png

Screenshot 2.jpg